Yoshihisa Yamamoto

All Publications

• Universal logic gates for quantum-dot electron-spin qubits using trapped quantum-well exciton polaritons PHYSICAL REVIEW B Puri, S., McMahon, P. L., Yamamoto, Y. 2017; 95 (12)

  View details for DOI 10.1103/PhysRevB.95.125410

  View details for Web of Science ID 000396012400003

• Combinatorial optimization using dynamical phase transitions in driven-dissipative systems PHYSICAL REVIEW E Leleu, T., Yamamoto, Y., Utsunomiya, S., Aihara, K. 2017; 95 (2)

  View details for DOI 10.1103/PhysRevE.95.022118

  View details for Web of Science ID 000393853300004

• Exciton-polariton trapping and potential landscape engineering REPORTS ON PROGRESS IN PHYSICS Schneider, C., Winkler, K., Fraser, M. D., Kamp, M., Yamamoto, Y., Ostrovskaya, E. A., Hoefling, S. 2017; 80 (1)

  Abstract

  Exciton-polaritons in semiconductor microcavities have become a model system for the studies of dynamical Bose-Einstein condensation, macroscopic coherence, many-body effects, nonclassical states of light and matter, and possibly quantum phase transitions in a solid state. These low-mass bosonic quasiparticles can condense at comparatively high temperatures up to 300 K, and preserve the fundamental properties of the condensate, such as coherence in space and time domain, even when they are out of equilibrium with the environment. Although the presence of a confining potential is not strictly necessary in order to observe Bose-Einstein condensation, engineering of the polariton confinement is a key to controlling, shaping, and directing the flow of polaritons. Prototype polariton-based optoelectronic devices rely on ultrafast photon-like velocities and strong nonlinearities exhibited by polaritons, as well as on their tailored confinement. Nanotechnology provides several pathways to achieving polariton confinement, and the specific features and advantages of different methods are discussed in this review. Being hybrid exciton-photon quasiparticles, polaritons can be trapped via their excitonic as well as photonic component, which leads to a wide choice of highly complementary trapping techniques. Here, we highlight the almost free choice of the confinement strengths and trapping geometries that provide powerful means for control and manipulation of the polariton systems both in the semi-classical and quantum regimes. Furthermore, the possibilities to observe effects of the polariton blockade, Mott insulator physics, and population of higher-order energy bands in sophisticated lattice potentials are discussed. Observation of such effects could lead to realization of novel polaritonic non-classical light sources and quantum simulators.

  View details for DOI 10.1088/0034-4885/80/1/016503

  View details for Web of Science ID 000388607300001

  View details for PubMedID 27841166

• Ultrafast coherent manipulation of trions in site-controlled nanowire quantum dots OPTICA Lagoudakis, K. G., McMahon, P. L., Dory, C., Fischer, K. A., Mueller, K., Borish, V., Dalacu, D., Poole, P. J., Reimer, M. E., Zwiller, V., Yamamoto, Y., Vuckovic, J. 2016; 3 (12): 1430-1435

  View details for DOI 10.1364/OPTICA.3.001430

  View details for Web of Science ID 000390793900023

• Reduced models and design principles for half-harmonic generation in synchronously pumped optical parametric oscillators PHYSICAL REVIEW A Hamerly, R., Marandi, A., Jankowski, M., Fejer, M. M., Yamamoto, Y., Mabuchi, H. 2016; 94 (6)

  View details for DOI 10.1103/PhysRevA.94.063809

  View details for Web of Science ID 000389023800008

• A fully programmable 100-spin coherent Ising machine with all-to-all connections. Science McMahon, P. L., Marandi, A., Haribara, Y., Hamerly, R., Langrock, C., Tamate, S., Inagaki, T., Takesue, H., Utsunomiya, S., Aihara, K., Byer, R. L., Fejer, M. M., Mabuchi, H., Yamamoto, Y. 2016; 354 (6312): 614-617

  Abstract

  Unconventional, special-purpose machines may aid in accelerating the solution of some of the hardest problems in computing, such as large-scale combinatorial optimizations, by exploiting different operating mechanisms than those of standard digital computers. We present a scalable optical processor with electronic feedback that can be realized at large scale with room-temperature technology. Our prototype machine is able to find exact solutions of, or sample good approximate solutions to, a variety of hard instances of Ising problems with up to 100 spins and 10,000 spin-spin connections.

  View details for PubMedID 27811274

• Topological defect formation in 1D and 2D spin chains realized by network of optical parametric oscillators INTERNATIONAL JOURNAL OF MODERN PHYSICS B Hamerly, R., Inaba, K., Inagaki, T., Takesue, H., Yamamoto, Y., Mabuchi, H. 2016; 30 (25)

  View details for DOI 10.1142/S0217979216300140

  View details for Web of Science ID 000385426000001

• Boltzmann Sampling by Degenerate Optical Parametric Oscillator Network for Structure-Based Virtual Screening ENTROPY Sakaguchi, H., Ogata, K., Isomura, T., Utsunomiya, S., Yamamoto, Y., Aihara, K. 2016; 18 (10)

  View details for DOI 10.3390/e18100365

  View details for Web of Science ID 000390100800023

• Physics and applications of exciton-polariton lasers NATURE MATERIALS Fraser, M. D., Hoefling, S., Yamamoto, Y. 2016; 15 (10): 1049-1052

  View details for DOI 10.1038/nmat4762

  View details for Web of Science ID 000384677100002

  View details for PubMedID 27658448

• A 16-bit Coherent Ising Machine for One-Dimensional Ring and Cubic Graph Problems SCIENTIFIC REPORTS Takata, K., Marandi, A., Hamerly, R., Haribara, Y., Maruo, D., Tamate, S., Sakaguchi, H., Utsunomiya, S., Yamamoto, Y. 2016; 6

  View details for DOI 10.1038/srep34089

  View details for Web of Science ID 000384075200001

• Truncated Wigner theory of coherent Ising machines based on degenerate optical parametric oscillator network PHYSICA SCRIPTA Maruo, D., Utsunomiya, S., Yamamoto, Y. 2016; 91 (8)

  View details for DOI 10.1088/0031-8949/91/8/083010

  View details for Web of Science ID 000384124500010

• Large-scale Ising spin network based on degenerate optical parametric oscillators NATURE PHOTONICS Inagaki, T., Inaba, K., Hamerly, R., Inoue, K., Yamamoto, Y., Takesue, H. 2016; 10 (6): 415-?

  View details for DOI 10.1038/NPHOTON.2016.68

  View details for Web of Science ID 000377476500020

• Initialization of a spin qubit in a site-controlled nanowire quantum dot NEW JOURNAL OF PHYSICS Lagoudakis, K. G., McMahon, P. L., Fischer, K. A., Puri, S., Mueller, K., Dalacu, D., Poole, P. J., Reimer, M. E., Zwiller, V., Yamamoto, Y., Vuckovic, J. 2016; 18

  View details for DOI 10.1088/1367-2630/18/5/053024

  View details for Web of Science ID 000377191500001

• Spatial correlation of two-dimensional bosonic multimode condensates PHYSICAL REVIEW A Nitsche, W. H., Kim, N. Y., Roumpos, G., Schneider, C., Hoefling, S., Forchel, A., Yamamoto, Y. 2016; 93 (5)

  View details for DOI 10.1103/PhysRevA.93.053622

  View details for Web of Science ID 000376631500015

• High-energy side-peak emission of exciton-polariton condensates in high density regime SCIENTIFIC REPORTS Horikiri, T., Yamaguchi, M., Kamide, K., Matsuo, Y., Byrnes, T., Ishida, N., Loeffler, A., Hoefling, S., Shikano, Y., Ogawa, T., Forchel, A., Yamamoto, Y. 2016; 6

  Abstract

  In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates-sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity-have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics.

  View details for DOI 10.1038/srep25655

  View details for Web of Science ID 000376372200001

  View details for PubMedID 27193700

  View details for PubMedCentralID PMC4872130

• Computational Principle and Performance Evaluation of Coherent Ising Machine Based on Degenerate Optical Parametric Oscillator Network ENTROPY Haribara, Y., Utsunomiya, S., Yamamoto, Y. 2016; 18 (4)

  View details for DOI 10.3390/e18040151

  View details for Web of Science ID 000375208200048

• Crossover from polariton lasing to exciton lasing in a strongly coupled ZnO microcavity. Scientific reports Lai, Y., Chou, Y., Lan, Y., Lu, T., Wang, S., Yamamoto, Y. 2016; 6: 20581-?

  Abstract

  Unlike conventional photon lasing, in which the threshold is limited by the population inversion of the electron-hole plasma, the exciton lasing generated by exciton-exciton scattering and the polariton lasing generated by dynamical condensates have received considerable attention in recent years because of the sub-Mott density and low-threshold operation. This paper presents a novel approach to generate both exciton and polariton lasing in a strongly coupled microcavity (MC) and determine the critical driving requirements for simultaneously triggering these two lasing operation in temperature <140 K and large negative polariton-exciton offset (<-133 meV) conditions. In addition, the corresponding lasing behaviors, such as threshold energy, linewidth, phase diagram, and angular dispersion are verified. The results afford a basis from which to understand the complicated lasing mechanisms in strongly coupled MCs and verify a new method with which to trigger dual laser emission based on exciton and polariton.

  View details for DOI 10.1038/srep20581

  View details for PubMedID 26838665

  View details for PubMedCentralID PMC4738341

• Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits NATURE COMMUNICATIONS Yu, L., Natarajan, C. M., Horikiri, T., Langrock, C., Pelc, J. S., Tanner, M. G., Abe, E., Maier, S., Schneider, C., Hoefling, S., Kamp, M., Hadfield, R. H., Fejer, M. M., Yamamoto, Y. 2015; 6

  Abstract

  Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances.

  View details for DOI 10.1038/ncomms9955

  View details for Web of Science ID 000366380800002

  View details for PubMedID 26597223

  View details for PubMedCentralID PMC4673878

• Observation of non-Hermitian degeneracies in a chaotic exciton-polariton billiard NATURE Gao, T., Estrecho, E., Bliokh, K. Y., Liew, T. C., Fraser, M. D., Brodbeck, S., Kamp, M., Schneider, C., Hoefling, S., Yamamoto, Y., Nori, F., Kivshar, Y. S., Truscott, A. G., Dall, R. G., Ostrovskaya, E. A. 2015; 526 (7574): 554-U203

  View details for DOI 10.1038/nature15522

  View details for Web of Science ID 000364026100046

  View details for PubMedID 26458102

• Quantum correlation in degenerate optical parametric oscillators with mutual injections PHYSICAL REVIEW A Takata, K., Marandi, A., Yamamoto, Y. 2015; 92 (4)

  View details for DOI 10.1103/PhysRevA.92.043821

  View details for Web of Science ID 000362890400004

• Spatial and temporal dynamics of the crossover from exciton-polariton condensation to photon lasing JAPANESE JOURNAL OF APPLIED PHYSICS Matsuo, Y., Fraser, M. D., Kusudo, K., Loeffler, A., Hoefling, S., Forchel, A., Yamamoto, Y. 2015; 54 (9)

  View details for DOI 10.7567/JJAP.54.092801

  View details for Web of Science ID 000362024900023

• Radiative properties of multicarrier bound excitons in GaAs PHYSICAL REVIEW B Karin, T., Barbour, R. J., Santori, C., Yamamoto, Y., Hirayama, Y., Fu, K. C. 2015; 91 (16)

  View details for DOI 10.1103/PhysRevB.91.165204

  View details for Web of Science ID 000353125400002

• Generating functional approach for spontaneous coherence in semiconductor electron-hole-photon systems PHYSICAL REVIEW B Yamaguchi, M., Nii, R., Kamide, K., Ogawa, T., Yamamoto, Y. 2015; 91 (11)

  View details for DOI 10.1103/PhysRevB.91.115129

  View details for Web of Science ID 000351037400001

• Binary phase oscillation of two mutually coupled semiconductor lasers OPTICS EXPRESS Utsunomiya, S., Namekata, N., Takata, K., Akamatsu, D., Inoue, S., Yamamoto, Y. 2015; 23 (5): 6029-6040

  Abstract

  A two-site Ising model is implemented as an injection-locked laser network consisting of a single master laser and two mutually coupled slave lasers. We observed ferromagnetic and antiferromagnetic orders in the in-phase and out-of-phase couplings between the two slave lasers. Their phase difference is locked to either 0 or π even if the coupling path is continuously modulated. The system automatically selects the oscillation frequency to satisfy the in-phase or out-of-phase coupling condition, when the mutual coupling dominates over the injection-locking by the master laser.

  View details for DOI 10.1364/OE.23.006029

  View details for Web of Science ID 000350878500057

  View details for PubMedID 25836827

• Verification of very strong coupling in a semiconductor optical microcavity NEW JOURNAL OF PHYSICS Yang, M., Kim, N. Y., Yamamoto, Y., Na, N. 2015; 17

  View details for DOI 10.1088/1367-2630/17/2/023064

  View details for Web of Science ID 000352867100002

• Photoluminescence of high-density exciton-polariton condensates PHYSICAL REVIEW B Ishida, N., Byrnes, T., Horikiri, T., Nori, F., Yamamoto, Y. 2014; 90 (24)

  View details for DOI 10.1103/PhysRevB.90.241304

  View details for Web of Science ID 000347124000002

• Network of time-multiplexed optical parametric oscillators as a coherent Ising machine NATURE PHOTONICS Marandi, A., Wang, Z., Takata, K., Byer, R. L., Yamamoto, Y. 2014; 8 (12): 937-942

  View details for DOI 10.1038/NPHOTON.2014.249

  View details for Web of Science ID 000345818600013

• Algebraic order and the Berezinskii-Kosterlitz-Thouless transition in an exciton-polariton gas PHYSICAL REVIEW B Nitsche, W. H., Kim, N. Y., Roumpos, G., Schneider, C., Kamp, M., Hofling, S., Forchel, A., Yamamoto, Y. 2014; 90 (20)

  View details for DOI 10.1103/PhysRevB.90.205430

  View details for Web of Science ID 000345538900010

• Exciton-polariton condensates NATURE PHYSICS Byrnes, T., Kim, N. Y., Yamamoto, Y. 2014; 10 (11): 803-813

  View details for DOI 10.1038/nphys3143

  View details for Web of Science ID 000344846700010

• Single-shot quantum nondemolition measurement of a quantum-dot electron spin using cavity exciton-polaritons PHYSICAL REVIEW B Puri, S., McMahon, P. L., Yamamoto, Y. 2014; 90 (15)

  View details for DOI 10.1103/PhysRevB.90.155421

  View details for Web of Science ID 000343771700004

• Effective interaction and condensation of dipolaritons in coupled quantum wells PHYSICAL REVIEW B Byrnes, T., Kolmakov, G. V., Kezerashvili, R. Y., Yamamoto, Y. 2014; 90 (12)

  View details for DOI 10.1103/PhysRevB.90.125314

  View details for Web of Science ID 000342137400006

• Ferminoic Physics in Dipolariton Condensates PHYSICAL REVIEW LETTERS Su, J., Kim, N. Y., Yamamoto, Y., MacDonald, A. H. 2014; 112 (11)

  Abstract

  An exciton polariton is an extremely light bosonic quasiparticle that is composed of an exciton and a photon. We report on a theoretical study of exciton-polariton condensation in a system with tunnel-coupled quantum wells. Because their excitons can carry an electric dipole moment, these systems have been referred to as dipolariton condensates. We use a fermionic mean-field theory that can address quantum well and other internal exciton degrees of freedom to describe the new physics present in dipolariton condensates. We find that the role of underlying fermonic degrees of freedom is enhanced and predict that metallic condensates can occur at high carrier densities.

  View details for DOI 10.1103/PhysRevLett.112.116401

  View details for Web of Science ID 000332924600015

  View details for PubMedID 24702391

• Data search by a coherent Ising machine based on an injection-locked laser network with gradual pumping or coupling PHYSICAL REVIEW A Takata, K., Yamamoto, Y. 2014; 89 (3)

  View details for DOI 10.1103/PhysRevA.89.032319

  View details for Web of Science ID 000333179100008

• BioHackathon series in 2011 and 2012: penetration of ontology and linked data in life science domains JOURNAL OF BIOMEDICAL SEMANTICS Katayama, T., Wilkinson, M. D., Aoki-Kinoshita, K. F., Kawashima, S., Yamamoto, Y., Yamaguchi, A., Okamoto, S., Kawano, S., Kim, J., Wang, Y., Wu, H., Kano, Y., Ono, H., Bono, H., Kocbek, S., Aerts, J., Akune, Y., Antezana, E., Arakawa, K., Aranda, B., Baran, J., Bolleman, J., Bonnal, R. J., Buttigieg, P. L., Campbell, M. P., Chen, Y., Chiba, H., Cock, P. J., Cohen, K. B., Constantin, A., Duck, G., Dumontier, M., Fujisawa, T., Fujiwara, T., Goto, N., Hoehndorf, R., Igarashi, Y., Itaya, H., Ito, M., Iwasaki, W., Kalas, M., Katoda, T., Kim, T., Kokubu, A., Komiyama, Y., Kotera, M., Laibe, C., Lapp, H., Luetteke, T., Marshall, M. S., Mori, T., Mori, H., Morita, M., Murakami, K., Nakao, M., Narimatsu, H., Nishide, H., Nishimura, Y., Nystrom-Persson, J., Ogishima, S., Okamura, Y., Okuda, S., Oshita, K., Packer, N. H., Prins, P., Ranzinger, R., Rocca-Serra, P., Sansone, S., Sawaki, H., Shin, S., Splendiani, A., Strozzi, F., Tadaka, S., Toukach, P., Uchiyama, I., Umezaki, M., Vos, R., Whetzel, P. L., Yamada, I., Yamasaki, C., Yamashita, R., York, W. S., Zmasek, C. M., Kawamoto, S., Takagi, T. 2014; 5

  Abstract

  The application of semantic technologies to the integration of biological data and the interoperability of bioinformatics analysis and visualization tools has been the common theme of a series of annual BioHackathons hosted in Japan for the past five years. Here we provide a review of the activities and outcomes from the BioHackathons held in 2011 in Kyoto and 2012 in Toyama. In order to efficiently implement semantic technologies in the life sciences, participants formed various sub-groups and worked on the following topics: Resource Description Framework (RDF) models for specific domains, text mining of the literature, ontology development, essential metadata for biological databases, platforms to enable efficient Semantic Web technology development and interoperability, and the development of applications for Semantic Web data. In this review, we briefly introduce the themes covered by these sub-groups. The observations made, conclusions drawn, and software development projects that emerged from these activities are discussed.

  View details for DOI 10.1186/2041-1480-5-5

  View details for Web of Science ID 000343707900001

  View details for PubMedID 24495517

  View details for PubMedCentralID PMC3978116

• Exciton-polariton laser diodes Conference on Nanophotonics and Micro/Nano Optics II Amthor, M., Fischer, J., Savenko, I. G., Shelykh, I. A., Chernenko, A., Rahimi-Iman, A., Kulakovskii, V. D., Reitzenstein, S., Kim, N. Y., Durnev, M., Kavokin, A. V., Yamamoto, Y., Forchel, A., Kamp, M., Schneider, C., Hoefling, S. SPIE-INT SOC OPTICAL ENGINEERING. 2014

  View details for DOI 10.1117/12.2074122

  View details for Web of Science ID 000349393300010

• Co-variation of Depressive Mood and Spontaneous Physical Activity Evaluated by Ecological Momentary Assessment in Major Depressive Disorder 36th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society (EMBC) Kim, J., Nakamura, T., Kikuchi, H., Yoshiuchi, K., Yamamoto, Y. IEEE. 2014: 6635–6638

  Abstract

  The objective evaluation of depressive mood is thought to be useful for the diagnosis and treatment of depressive disorders. Thus, we investigated psychobehavioral correlates, particularly the statistical associations between momentary depressive mood and behavioral dynamics measured objectively, in patients with major depressive disorder (MDD). Patients with MDD (n = 14) wore a watch-type computer device and rated their momentary symptoms using ecological momentary assessment. Spontaneous physical activity in daily life, referred to as locomotor activity, was also continuously measured by an activity monitor built into the device. A multilevel modeling approach was used to model the associations between changes in depressive mood scores and the local statistics of locomotor activity simultaneously measured. The statistical model constructed indicated that worsening of depressive mood was associated with increased intermittency of locomotor activity, as characterized by a lower mean and higher skewness. Our findings suggest the presence of associations between momentary depressive mood and behavioral dynamics in patients with depression, which may lead to the continuous monitoring of the pathological states of MDD.

  View details for Web of Science ID 000350044706153

  View details for PubMedID 25571517

• Coherent Ising machine based on degenerate optical parametric oscillators PHYSICAL REVIEW A Wang, Z., Marandi, A., Wen, K., Byer, R. L., Yamamoto, Y. 2013; 88 (6)

  View details for DOI 10.1103/PhysRevA.88.063853

  View details for Web of Science ID 000332108400018

• Ultrafast optical control of individual quantum dot spin qubits. Reports on progress in physics. Physical Society (Great Britain) Greve, K. D., Press, D., McMahon, P. L., Yamamoto, Y. 2013; 76 (9): 092501-?

  Abstract

  Single spins in semiconductor quantum dots form a promising platform for solid-state quantum information processing. The spin-up and spin-down states of a single electron or hole, trapped inside a quantum dot, can represent a single qubit with a reasonably long decoherence time. The spin qubit can be optically coupled to excited (charged exciton) states that are also trapped in the quantum dot, which provides a mechanism to quickly initialize, manipulate and measure the spin state with optical pulses, and to interface between a stationary matter qubit and a 'flying' photonic qubit for quantum communication and distributed quantum information processing. The interaction of the spin qubit with light may be enhanced by placing the quantum dot inside a monolithic microcavity. An entire system, consisting of a two-dimensional array of quantum dots and a planar microcavity, may plausibly be constructed by modern semiconductor nano-fabrication technology and could offer a path toward chip-sized scalable quantum repeaters and quantum computers. This article reviews the recent experimental developments in optical control of single quantum dot spins for quantum information processing. We highlight demonstrations of a complete set of all-optical single-qubit operations on a single quantum dot spin: initialization, an arbitrary SU(2) gate, and measurement. We review the decoherence and dephasing mechanisms due to hyperfine interaction with the nuclear-spin bath, and show how the single-qubit operations can be combined to perform spin echo sequences that extend the qubit decoherence from a few nanoseconds to several microseconds, more than 5 orders of magnitude longer than the single-qubit gate time. Two-qubit coupling is discussed, both within a single chip by means of exchange coupling of nearby spins and optically induced geometric phases, as well as over longer-distances. Long-distance spin-spin entanglement can be generated if each spin can emit a photon that is entangled with the spin, and these photons are then interfered. We review recent work demonstrating entanglement between a stationary spin qubit and a flying photonic qubit. These experiments utilize the polarization- and frequency-dependent spontaneous emission from the lowest charged exciton state to single spin Zeeman sublevels.

  View details for DOI 10.1088/0034-4885/76/9/092501

  View details for PubMedID 24006335

• Neural networks using two-component Bose-Einstein condensates SCIENTIFIC REPORTS Byrnes, T., Koyama, S., Yan, K., Yamamoto, Y. 2013; 3

  Abstract

  The authors previously considered a method of solving optimization problems by using a system of interconnected network of two component Bose-Einstein condensates (Byrnes, Yan, Yamamoto New J. Phys. 13, 113025 (2011)). The use of bosonic particles gives a reduced time proportional to the number of bosons N for solving Ising model Hamiltonians by taking advantage of enhanced bosonic cooling rates. Here we consider the same system in terms of neural networks. We find that up to the accelerated cooling of the bosons the previously proposed system is equivalent to a stochastic continuous Hopfield network. This makes it clear that the BEC network is a physical realization of a simulated annealing algorithm, with an additional speedup due to bosonic enhancement. We discuss the BEC network in terms of neural network tasks such as learning and pattern recognition and find that the latter process may be accelerated by a factor of N.

  View details for DOI 10.1038/srep02531

  View details for Web of Science ID 000323695900001

  View details for PubMedID 23989391

  View details for PubMedCentralID PMC3757363

• Temperature Dependence of Highly Excited Exciton Polaritons in Semiconductor Microcavities JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN Horikiri, T., Matsuo, Y., Shikano, Y., Loeffler, A., Hoefling, S., Forchel, A., Yamamoto, Y. 2013; 82 (8)

  View details for DOI 10.7566/JPSJ.82.084709

  View details for Web of Science ID 000322374300036

• Complete tomography of a high-fidelity solid-state entangled spin-photon qubit pair. Nature communications De Greve, K., McMahon, P. L., Yu, L., Pelc, J. S., Jones, C., Natarajan, C. M., Kim, N. Y., Abe, E., Maier, S., Schneider, C., Kamp, M., Höfling, S., Hadfield, R. H., Forchel, A., Fejer, M. M., Yamamoto, Y. 2013; 4: 2228-?

  Abstract

  Entanglement between stationary quantum memories and photonic qubits is crucial for future quantum communication networks. Although high-fidelity spin-photon entanglement was demonstrated in well-isolated atomic and ionic systems, in the solid-state, where massively parallel, scalable networks are most realistically conceivable, entanglement fidelities are typically limited due to intrinsic environmental interactions. Distilling high-fidelity entangled pairs from lower-fidelity precursors can act as a remedy, but the required overhead scales unfavourably with the initial entanglement fidelity. With spin-photon entanglement as a crucial building block for entangling quantum network nodes, obtaining high-fidelity entangled pairs becomes imperative for practical realization of such networks. Here we report the first results of complete state tomography of a solid-state spin-photon-polarization-entangled qubit pair, using a single electron-charged indium arsenide quantum dot. We demonstrate record-high fidelity in the solid-state of well over 90%, and the first (99.9%-confidence) achievement of a fidelity that will unambiguously allow for entanglement distribution in solid-state quantum repeater networks.

  View details for DOI 10.1038/ncomms3228

  View details for PubMedID 23887066

• Second Thresholds in BEC-BCS-Laser Crossover of Exciton-Polariton Systems PHYSICAL REVIEW LETTERS Yamaguchi, M., Kamide, K., Nii, R., Ogawa, T., Yamamoto, Y. 2013; 111 (2)

  Abstract

  The mechanism of second thresholds observed in several experiments is theoretically revealed by studying the BEC-BCS-laser crossover in exciton-polariton systems. We find that there are two different types of second thresholds: one is a crossover within quasiequilibrium phases and the other is into nonequilibrium (lasing). In both cases, the light-induced band renormalization causes gaps in the conduction and valence bands, which indicates the existence of bound electron-hole pairs in contrast to earlier expectations. We also show that these two types can be distinguished by the gain spectra.

  View details for DOI 10.1103/PhysRevLett.111.026404

  View details for Web of Science ID 000321856600006

  View details for PubMedID 23889425

• Faster quantum chemistry simulation on fault-tolerant quantum computers NEW JOURNAL OF PHYSICS Jones, N. C., Whitfield, J. D., McMahon, P. L., Yung, M., Van Meter, R., Aspuru-Guzik, A., Yamamoto, Y. 2012; 14

  View details for DOI 10.1088/1367-2630/14/11/115023

  View details for Web of Science ID 000311582300002

• Quantum-dot spin-photon entanglement via frequency downconversion to telecom wavelength NATURE De Greve, K., Yu, L., McMahon, P. L., Pelc, J. S., Natarajan, C. M., Kim, N. Y., Abe, E., Maier, S., Schneider, C., Kamp, M., Hoefling, S., Hadfield, R. H., Forchel, A., Fejer, M. M., Yamamoto, Y. 2012; 491 (7424): 421-?

  Abstract

  Long-distance quantum teleportation and quantum repeater technologies require entanglement between a single matter quantum bit (qubit) and a telecommunications (telecom)-wavelength photonic qubit. Electron spins in III-V semiconductor quantum dots are among the matter qubits that allow for the fastest spin manipulation and photon emission, but entanglement between a single quantum-dot spin qubit and a flying (propagating) photonic qubit has yet to be demonstrated. Moreover, many quantum dots emit single photons at visible to near-infrared wavelengths, where silica fibre losses are so high that long-distance quantum communication protocols become difficult to implement. Here we demonstrate entanglement between an InAs quantum-dot electron spin qubit and a photonic qubit, by frequency downconversion of a spontaneously emitted photon from a singly charged quantum dot to a wavelength of 1,560 nanometres. The use of sub-10-picosecond pulses at a wavelength of 2.2 micrometres in the frequency downconversion process provides the necessary quantum erasure to eliminate which-path information in the photon energy. Together with previously demonstrated indistinguishable single-photon emission at high repetition rates, the present technique advances the III-V semiconductor quantum-dot spin system as a promising platform for long-distance quantum communication.

  View details for DOI 10.1038/nature11577

  View details for Web of Science ID 000311031600041

  View details for PubMedID 23151585

• Quantum Computing vs. Coherent Computing NEW GENERATION COMPUTING Yamamoto, Y., Takata, K., Utsunomiya, S. 2012; 30 (4): 327-355

  View details for DOI 10.1007/s00354-012-0403-5

  View details for Web of Science ID 000310870700003

• Entangling Single Photons from Independently Tuned Semiconductor Nanoemitters NANO LETTERS Sanaka, K., Pawlis, A., Ladd, T. D., Sleiter, L. J., Lischka, K., Yamamoto, Y. 2012; 12 (9): 4611-4616

  Abstract

  Quantum communication systems based on nanoscale semiconductor devices is challenged by inhomogeneities from device to device. We address this challenge using ZnMgSe/ZnSe quantum-well nanostructures with local laser-based heating to tune the emission of single impurity-bound exciton emitters in two separate devices. The matched emission in combination with photon bunching enables quantum interference from the devices and allows the postselection of polarization-entangled single photons. The ability to entangle single photons emitted from nanometer-sized sources separated by macroscopic distances provides an essential step for a solid-state realization of a large-scale quantum optical network. This paves the way toward measurement-based entanglement generation between remote electron spins localized at macroscopically separated fluorine impurities.

  View details for DOI 10.1021/nl301911t

  View details for Web of Science ID 000308576000032

  View details for PubMedID 22839419

• Layered Architecture for Quantum Computing PHYSICAL REVIEW X Jones, N. C., Van Meter, R., Fowler, A. G., McMahon, P. L., Kim, J., Ladd, T. D., Yamamoto, Y. 2012; 2 (3)

  View details for DOI 10.1103/PhysRevX.2.031007

  View details for Web of Science ID 000310514300003

• Two-qubit geometric phase gate for quantum dot spins using cavity polariton resonance PHYSICAL REVIEW B Puri, S., Kim, N. Y., Yamamoto, Y. 2012; 85 (24)

  View details for DOI 10.1103/PhysRevB.85.241403

  View details for Web of Science ID 000305253600002

• Exciton-polariton condensates with flat bands in a two-dimensional kagome lattice NEW JOURNAL OF PHYSICS Masumoto, N., Kim, N. Y., Byrnes, T., Kusudo, K., Loeffler, A., Hoefling, S., Forchel, A., Yamamoto, Y. 2012; 14

  View details for DOI 10.1088/1367-2630/14/6/065002

  View details for Web of Science ID 000306931900002

• BEC-BCS-laser crossover in Coulomb-correlated electron-hole-photon systems NEW JOURNAL OF PHYSICS Yamaguchi, M., Kamide, K., Ogawa, T., Yamamoto, Y. 2012; 14

  View details for DOI 10.1088/1367-2630/14/6/065001

  View details for Web of Science ID 000306931900001

• Macroscopic quantum computation using Bose-Einstein condensates PHYSICAL REVIEW A Byrnes, T., Wen, K., Yamamoto, Y. 2012; 85 (4)

  View details for DOI 10.1103/PhysRevA.85.040306

  View details for Web of Science ID 000303192000001

• Power-law decay of the spatial correlation function in exciton-polariton condensates PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Roumpos, G., Lohse, M., Nitsche, W. H., Keeling, J., Szymanska, M. H., Littlewood, P. B., Loeffler, A., Hoefling, S., Worschech, L., Forchel, A., Yamamoto, Y. 2012; 109 (17): 6467-6472

  Abstract

  We create a large exciton-polariton condensate and employ a Michelson interferometer setup to characterize the short- and long-distance behavior of the first order spatial correlation function. Our experimental results show distinct features of both the two-dimensional and nonequilibrium characters of the condensate. We find that the gaussian short-distance decay is followed by a power-law decay at longer distances, as expected for a two-dimensional condensate. The exponent of the power law is measured in the range 0.9-1.2, larger than is possible in equilibrium. We compare the experimental results to a theoretical model to understand the features required to observe a power law and to clarify the influence of external noise on spatial coherence in nonequilibrium phase transitions. Our results indicate that Berezinskii-Kosterlitz-Thouless-like phase order survives in open-dissipative systems.

  View details for DOI 10.1073/pnas.1107970109

  View details for Web of Science ID 000303249100032

  View details for PubMedID 22496595

  View details for PubMedCentralID PMC3340049

• Spin dephasing of fluorine-bound electrons in ZnSe PHYSICAL REVIEW B Greilich, A., Pawlis, A., Liu, F., Yugov, O. A., Yakovlev, D. R., Lischka, K., Yamamoto, Y., Bayer, M. 2012; 85 (12)

  View details for DOI 10.1103/PhysRevB.85.121303

  View details for Web of Science ID 000301517900002

• Negative Bogoliubov dispersion in exciton-polariton condensates PHYSICAL REVIEW B Byrnes, T., Horikiri, T., Ishida, N., Fraser, M., Yamamoto, Y. 2012; 85 (7)

  View details for DOI 10.1103/PhysRevB.85.075130

  View details for Web of Science ID 000300935000002

• Cascaded frequency upconversion for high-speed single-photon detection at 1550 nm OPTICS LETTERS Pelc, J. S., Zhang, Q., Phillips, C. R., Yu, L., Yamamoto, Y., Fejer, M. M. 2012; 37 (4): 476-478

  Abstract

  We present a device for two-stage frequency upconversion of single-photon-level signals in the 1.55 μm telecom band to the green spectral region with low excess noise, suitable for detection by low-timing-jitter silicon single-photon avalanche photodiodes (APDs). We achieve a net conversion efficiency of 87% and a system timing jitter below 70 ps FWHM, dominated by the jitter of the APD. Modifications of our device are suitable for downconversion of single photons from visible-wavelength quantum emitters into the telecom band.

  View details for Web of Science ID 000300706500011

  View details for PubMedID 22344078

• Semiconductor qubits based on fluorine implanted ZnMgSe/ZnSe quantum-well nanostructures PHYSICAL REVIEW B Kim, Y. M., Sleiter, D., Sanaka, K., Yamamoto, Y., Meijer, J., Lischka, K., Pawlis, A. 2012; 85 (8)

  View details for DOI 10.1103/PhysRevB.85.085302

  View details for Web of Science ID 000299902200003

• Transient time of an Ising machine based on injection-locked laser network NEW JOURNAL OF PHYSICS Takata, K., Utsunomiya, S., Yamamoto, Y. 2012; 14

  View details for DOI 10.1088/1367-2630/14/1/013052

  View details for Web of Science ID 000300413900006

• Direct photoluminescence observation of the negative Bogoliubov branch in an exciton-polariton condensate Conference on Lasers and Electro-Optics (CLEO) Horikiri, T., Byrnes, T., Ishida, N., Loeffler, A., Hoefling, S., Forchel, A., Yamamoto, Y. IEEE. 2012

  View details for Web of Science ID 000310362402486

• GaN-based microcavity polariton light emitting diodes Conference on Light-Emitting Diodes - Materials, Devices, and Applications for Solid State Lighting XVI Lu, T., Lai, Y., Huang, S., Chen, J., Wu, Y., Lin, S., Wang, S., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2012

  View details for DOI 10.1117/12.908343

  View details for Web of Science ID 000301055700010

• REMOVAL PROPERTIES OF REACTION SINTERED SIC IN ATMOSPHERIC PRESSURE PLASMA FABRICATION PROCESS 10th International Conference on Progress of Machining Technology (ICPMT2012) Yamamura, K., Yamamoto, Y., Hata, Y., Deng, H. JAPAN SOC PRECISION ENGINEERING-JSPE. 2012: 203–206

  View details for Web of Science ID 000327044000050

• Fault-tolerant quantum repeaters for long-distance quantum communication based on quantum dots Conference on Lasers and Electro-Optics (CLEO) Jones, N. C., De Greve, K., Yamamoto, Y. IEEE. 2012

  View details for Web of Science ID 000310362402235

• Preliminary Study on Chemical Figuring and Finishing of Sintered SiC Substrate Using Atmospheric Pressure Plasma 45th CIRP Conference on Manufacturing Systems (CIRP CMS) Yamamura, K., Yamamoto, Y., Deng, H. ELSEVIER SCIENCE BV. 2012: 335–339

  View details for DOI 10.1016/j.procir.2012.07.058

  View details for Web of Science ID 000314630700057

• High-Speed Single-Photon Detection at 1550 nm via Cascaded Frequency Upconversion Conference on Lasers and Electro-Optics (CLEO) Pelc, J. S., Zhang, Q., Phillips, C. R., Yu, L., Yamamoto, Y., Fejer, M. M. IEEE. 2012

  View details for Web of Science ID 000310362402045

• Optical properties of fluorine implanted ZnMgSe/ZnSe quantum-well nanostructures Conference on Advances in Photonics of Quantum Computing, Memory, and Communication V Kim, Y. M., Sleiter, D., Sanaka, K., Yamamoto, Y., Meijer, J., Lischka, K., Pawlis, A. SPIE-INT SOC OPTICAL ENGINEERING. 2012

  View details for DOI 10.1117/12.908173

  View details for Web of Science ID 000304136300014

• Phase-coherent high-orbital microcavity exciton-polaritons in a lattice Conference on Lasers and Electro-Optics (CLEO) Kim, N. Y., Kusudo, K., Hoefling, S., Forchel, A., Yamamoto, Y. IEEE. 2012

  View details for Web of Science ID 000310362403168

• Simple quantum logic gate with quantum dot cavity QED systems PHYSICAL REVIEW B Ladd, T. D., Yamamoto, Y. 2011; 84 (23)

  View details for DOI 10.1103/PhysRevB.84.235307

  View details for Web of Science ID 000303509000008

• Accelerated optimization problem search using Bose-Einstein condensation NEW JOURNAL OF PHYSICS Byrnes, T., Yan, K., Yamamoto, Y. 2011; 13

  View details for DOI 10.1088/1367-2630/13/11/113025

  View details for Web of Science ID 000297576900002

• Ultrafast coherent control and suppressed nuclear feedback of a single quantum dot hole qubit NATURE PHYSICS De Greve, K., McMahon, P. L., Press, D., Ladd, T. D., Bisping, D., Schneider, C., Kamp, M., Worschech, L., Hoefling, S., Forchel, A., Yamamoto, Y. 2011; 7 (11): 872-878

  View details for DOI 10.1038/NPHYS2078

  View details for Web of Science ID 000296740000016

• Present Status and Future Prospects of Quantum Information Processing: With Special Focus on Optically Controlled Semiconductor Spins and Single-Photon Technologies JAPANESE JOURNAL OF APPLIED PHYSICS Yamamoto, Y. 2011; 50 (10)

  View details for DOI 10.1143/JJAP.50.100001

  View details for Web of Science ID 000296085700001

• Mapping of Ising models onto injection-locked laser systems OPTICS EXPRESS Utsunomiya, S., Takata, K., Yamamoto, Y. 2011; 19 (19): 18091-18108

  Abstract

  We propose a mapping protocol to implement Ising models in injection-locked laser systems. The proposed scheme is based on optical coherent feedback and can be potentially applied for large-scale Ising problems.

  View details for Web of Science ID 000294781200039

  View details for PubMedID 21935175

• Dynamical d-wave condensation of exciton-polaritons in a two-dimensional square-lattice potential NATURE PHYSICS Kim, N. Y., Kusudo, K., Wu, C., Masumoto, N., Loeffler, A., Hoefling, S., Kumada, N., Worschech, L., Forchel, A., Yamamoto, Y. 2011; 7 (9): 681-686

  View details for DOI 10.1038/NPHYS2012

  View details for Web of Science ID 000294485400012

• Possible origin of the nonmonotonic doping dependence of the in-plane resistivity anisotropy of Ba(Fe(1)xT(x))(2)As-2 (T = Co, Ni and Cu) PHYSICAL REVIEW B Kuo, H., Chu, J., Riggs, S. C., Yu, L., McMahon, P. L., De Greve, K., Yamamoto, Y., Analytis, J. G., Fisher, I. R. 2011; 84 (5)

  View details for DOI 10.1103/PhysRevB.84.054540

  View details for Web of Science ID 000293829800022

• Room Temperature Current Injection Polariton Light Emitting Diode with a Hybrid Microcavity NANO LETTERS Lu, T., Chen, J., Lin, S., Huang, S., Wang, S., Yamamoto, Y. 2011; 11 (7): 2791-2795

  Abstract

  The strong light-matter interaction within a semiconductor high-Q microcavity has been used to produce half-matter/half-light quasiparticles, exciton-polaritons. The exciton-polaritons have very small effective mass and controllable energy-momentum dispersion relation. These unique properties of polaritons provide the possibility to investigate the fundamental physics including solid-state cavity quantum electrodynamics, and dynamical Bose-Einstein condensates (BECs). Thus far the polariton BEC has been demonstrated using optical excitation. However, from a practical viewpoint, the current injection polariton devices operating at room temperature would be most desirable. Here we report the first realization of a current injection microcavity GaN exciton-polariton light emitting diode (LED) operating under room temperature. The exciton-polariton emission from the LED at photon energy 3.02 eV under strong coupling condition is confirmed through temperature-dependent and angle-resolved electroluminescence spectra.

  View details for DOI 10.1021/nl2011164

  View details for Web of Science ID 000292849400039

  View details for PubMedID 21675759

• Resource analysis for quantum simulation on a fault-tolerant quantum computer 241st National Meeting and Exposition of the American-Chemical-Society (ACS) Jones, N. C., McMahon, P. L., Whitfield, J., Yung, M., Aspuru-Guzik, A., Yamamoto, Y. AMER CHEMICAL SOC. 2011

  View details for Web of Science ID 000291982804102

• Single vortex-antivortex pair in an exciton-polariton condensate NATURE PHYSICS Roumpos, G., Fraser, M. D., Loeffler, A., Hoefling, S., Forchel, A., Yamamoto, Y. 2011; 7 (2): 129-133

  View details for DOI 10.1038/NPHYS1841

  View details for Web of Science ID 000286807000014

• Inhibition of Allergic Bronchial Asthma by Thrombomodulin Is Mediated by Dendritic Cells AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Takagi, T., Taguchi, O., Toda, M., Ruiz, D. B., Bernabe, P. G., D'Alessandro-Gabazza, C. N., Miyake, Y., Kobayashi, T., Aoki, S., Chiba, F., Yano, Y., Conway, E. M., Munesue, S., Yamamoto, Y., Yamamoto, H., Suzuki, K., Takei, Y., Morser, J., Gabazza, E. C. 2011; 183 (1): 31-42

  Abstract

  bronchial asthma is caused by inappropriate acquired immune responses to environmental allergens. It is a major health problem, with a prevalence that is rapidly increasing. Curative therapy is not currently available.to test the hypothesis that thrombomodulin (TM) inhibits allergic bronchial asthma by inducing tolerogenic dendritic cells (DCs).the protective effect of TM was evaluated using a murine asthma model. Asthma was induced in mice by exposure to chicken egg ovalbumin, and the effects of inhaled TM or TM-treated DCs were assessed by administering before ovalbumin exposure.treatment with TM protects against bronchial asthma measured as improved lung function and reduced IgE and cells in alveolar lavage fluid by inducing tolerogenic dendritic dells. These are characterized by high expression of surface TM (CD141/TM(+)) and low expression of maturation markers and possess reduced T-cell costimulatory activity. The CD141/TM(+) DCs migrate less toward chemokines, and after TM treatment there are fewer DCs in the draining lymph node and more in the lungs. The TM effect is independent of its role in coagulation. Rather, it is mediated via the TM lectin domain directly interacting with the DCs.the results of this study show that TM is a modulator of DC immunostimulatory properties and a novel candidate drug for the prevention of bronchial asthma in atopic patients.

  View details for DOI 10.1164/rccm.201001-0107OC

  View details for Web of Science ID 000286155600008

  View details for PubMedID 20709825

• Nuclear Feedback in a Single Electron-Charged Quantum Dot under Pulsed Optical Control Conference on Advances in Photonics of Quantum Computing, Memory, and Communication IV Ladd, T. D., Press, D., De Greve, K., McMahon, P. L., Friess, B., Schneider, C., Kamp, M., Hoefling, S., Forchel, A., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2011

  View details for DOI 10.1117/12.873978

  View details for Web of Science ID 000293702100015

• Photon antibunching and magnetospectroscopy of a single fluorine donor in ZnSe APPLIED PHYSICS LETTERS De Greve, K., Clark, S. M., Sleiter, D., Sanaka, K., Ladd, T. D., Panfilova, M., Pawlis, A., Lischka, K., Yamamoto, Y. 2010; 97 (24)

  View details for DOI 10.1063/1.3525579

  View details for Web of Science ID 000285481000025

• Massive parallel generation of indistinguishable single photons via the polaritonic superfluid to Mott-insulator quantum phase transition NEW JOURNAL OF PHYSICS Na, N., Yamamoto, Y. 2010; 12

  View details for DOI 10.1088/1367-2630/12/12/123001

  View details for Web of Science ID 000285013800001

• BCS Wave-Function Approach to the BEC-BCS Crossover of Exciton-Polariton Condensates PHYSICAL REVIEW LETTERS Byrnes, T., Horikiri, T., Ishida, N., Yamamoto, Y. 2010; 105 (18)

  Abstract

  The crossover between low and high density regimes of exciton-polariton condensates is examined using a BCS wave-function approach. Our approach is an extension of the BEC-BCS crossover theory for excitons, but includes a cavity photon field. The approach can describe both the low density limit, where the system can be described as a Bose-Einstein condensate (BEC) of exciton-polaritons, and the high density limit, where the system enters a photon-dominated regime. In contrast to the exciton BEC-BCS crossover where the system approaches an electron-hole plasma, the polariton high density limit has strongly correlated electron-hole pairs. At intermediate densities, there is a regime with BCS-like properties, with a peak at nonzero momentum of the singlet pair function. We calculate the expected photoluminescence and give several experimental signatures of the crossover.

  View details for DOI 10.1103/PhysRevLett.105.186402

  View details for Web of Science ID 000283492000007

  View details for PubMedID 21231119

• Quantum Hall charge sensor for single-donor nuclear spin detection in silicon NEW JOURNAL OF PHYSICS Sleiter, D., Kim, N. Y., Nozawa, K., Ladd, T. D., Thewalt, M. L., Yamamoto, Y. 2010; 12

  View details for DOI 10.1088/1367-2630/12/9/093028

  View details for Web of Science ID 000281901900001

• Pulsed Nuclear Pumping and Spin Diffusion in a Single Charged Quantum Dot PHYSICAL REVIEW LETTERS Ladd, T. D., Press, D., De Greve, K., McMahon, P. L., Friess, B., Schneider, C., Kamp, M., Hoefling, S., Forchel, A., Yamamoto, Y. 2010; 105 (10)

  Abstract

  We report the observation of a feedback process between the nuclear spins in a single charged quantum dot under coherently pulsed optical excitation and its trion transition. The optical pulse sequence intersperses resonant narrow-band pumping for spin initialization with off-resonant ultrafast pulses for coherent electron-spin rotation. A hysteretic sawtooth pattern in the free-induction decay of the single electron spin is observed; a mathematical model indicates a competition between optical nuclear pumping and nuclear spin-diffusion. This effect allows dynamic tuning of the electron Larmor frequency to a value determined by the pulse timing, potentially allowing more complex coherent control operations.

  View details for DOI 10.1103/PhysRevLett.105.107401

  View details for Web of Science ID 000281486900011

  View details for PubMedID 20867546

• In-Plane Resistivity Anisotropy in an Underdoped Iron Arsenide Superconductor SCIENCE Chu, J., Analytis, J. G., De Greve, K., McMahon, P. L., Islam, Z., Yamamoto, Y., Fisher, I. R. 2010; 329 (5993): 824-826

  Abstract

  High-temperature superconductivity often emerges in the proximity of a symmetry-breaking ground state. For superconducting iron arsenides, in addition to the antiferromagnetic ground state, a small structural distortion breaks the crystal's C(4 )rotational symmetry in the underdoped part of the phase diagram. We reveal that the representative iron arsenide Ba(Fe(1)(-x)Co(x))(2)As(2) develops a large electronic anisotropy at this transition via measurements of the in-plane resistivity of detwinned single crystals, with the resistivity along the shorter b axis rho(b) being greater than rho(a). The anisotropy reaches a maximum value of ~2 for compositions in the neighborhood of the beginning of the superconducting dome. For temperatures well above the structural transition, uniaxial stress induces a resistivity anisotropy, indicating a substantial nematic susceptibility.

  View details for DOI 10.1126/science.1190482

  View details for Web of Science ID 000280809900046

  View details for PubMedID 20705856

• In-plane electronic anisotropy in underdoped Ba(Fe1-xCox)(2)As-2 revealed by partial detwinning in a magnetic field PHYSICAL REVIEW B Chu, J., Analytis, J. G., Press, D., De Greve, K., Ladd, T. D., Yamamoto, Y., Fisher, I. R. 2010; 81 (21)

  View details for DOI 10.1103/PhysRevB.81.214502

  View details for Web of Science ID 000278300700004

• Ultrafast optical spin echo in a single quantum dot NATURE PHOTONICS Press, D., De Greve, K., McMahon, P. L., Ladd, T. D., Friess, B., Schneider, C., Kamp, M., Hoefling, S., Forchel, A., Yamamoto, Y. 2010; 4 (6): 367-370

  View details for DOI 10.1038/NPHOTON.2010.83

  View details for Web of Science ID 000278422200013

• Fluorine-doped ZnSe for applications in quantum information processing PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Ladd, T. D., Sanaka, K., Yamamoto, Y., Pawlis, A., Lischka, K. 2010; 247 (6): 1543-1546

  View details for DOI 10.1002/pssb.200983258

  View details for Web of Science ID 000279080300046

• Hong-Ou-Mandel Dip Using Degenerate Photon Pairs from a Single Periodically Poled Lithium Niobate Waveguide with Integrated Mode Demultiplexer JAPANESE JOURNAL OF APPLIED PHYSICS Zhang, Q., Takesue, H., Langrock, C., Xie, X., Fejer, M. M., Yamamoto, Y. 2010; 49 (6)

  View details for DOI 10.1143/JJAP.49.064401

  View details for Web of Science ID 000278963000053

• Mott transitions of exciton polaritons and indirect excitons in a periodic potential PHYSICAL REVIEW B Byrnes, T., Recher, P., Yamamoto, Y. 2010; 81 (20)

  View details for DOI 10.1103/PhysRevB.81.205312

  View details for Web of Science ID 000278144500064

• Exciton-polariton Bose-Einstein condensation REVIEWS OF MODERN PHYSICS Deng, H., Haug, H., Yamamoto, Y. 2010; 82 (2): 1489-1537

  View details for DOI 10.1103/RevModPhys.82.1489

  View details for Web of Science ID 000278228800001

• Gain-Induced Trapping of Microcavity Exciton Polariton Condensates PHYSICAL REVIEW LETTERS Roumpos, G., Nitsche, W. H., Hoefling, S., Forchel, A., Yamamoto, Y. 2010; 104 (12)

  Abstract

  We have performed real and momentum space spectroscopy of exciton polariton condensates in a GaAs-based microcavity under nonresonant excitation with an intensity-stabilized laser. An effective trapping mechanism is revealed, which is due to the stimulated scattering gain inside the finite excitation spot combined with the short lifetime. We observe several quantized modes while the lowest state shows Heisenberg-limited real and momentum space distributions. The experimental findings are qualitatively reproduced by an open dissipative Gross-Pitaevskii equation model.

  View details for DOI 10.1103/PhysRevLett.104.126403

  View details for Web of Science ID 000276072400038

  View details for PubMedID 20366554

• DISTRIBUTED QUANTUM COMPUTATION ARCHITECTURE USING SEMICONDUCTOR NANOPHOTONICS INTERNATIONAL JOURNAL OF QUANTUM INFORMATION Van Meter, R., Ladd, T. D., Fowler, A. G., Yamamoto, Y. 2010; 8 (1-2): 295-323

  View details for DOI 10.1142/S0219749910006435

  View details for Web of Science ID 000278194600012

• Higher order coherence of exciton-polariton condensates PHYSICAL REVIEW B Horikiri, T., Schwendimann, P., Quattropani, A., Hoefling, S., Forchel, A., Yamamoto, Y. 2010; 81 (3)

  View details for DOI 10.1103/PhysRevB.81.033307

  View details for Web of Science ID 000274002300015

• Spin echo of electron spins in semiconductors using ultrafast, small-angle, optical pulses Conference on Advances in Photonics of Quantum Computing, Memory, and Communication III Clark, S. M., Fu, K. C., Zhang, Q., Ladd, T. D., Stanley, C., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2010

  View details for DOI 10.1117/12.841210

  View details for Web of Science ID 000284307900005

• Spin transition induced by crystal - liquid crystal transition International Conference on Magnetism (ICM 2009) Hayami, S., Yamamoto, Y., Kojima, Y., Inoue, K. IOP PUBLISHING LTD. 2010

  View details for DOI 10.1088/1742-6596/200/8/082008

  View details for Web of Science ID 000291321303046

• Experimental approach to ultrafast optical spin echo of a single quantum dot electron spin Conference on Advances in Photonics of Quantum Computing, Memory, and Communication III De Greve, K., Press, D., Ladd, T. D., Friess, B., McMahon, P. L., Schneider, C., Kamp, M., Hoefling, S., Forchel, A., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2010

  View details for DOI 10.1117/12.843667

  View details for Web of Science ID 000284307900006

• Electrically Pumped Photonic Crystal Nanocavities Using a Laterally Doped p-i-n Junction Conference on Lasers and Electro-Optics (CLEO)/Quantum Electronics and Laser Science Conference (QELS) Ellis, B., Sarmiento, T., Mayer, M., Stone, P., Beeman, J., Zhang, B., Dubon, O., Haller, E., Yamamoto, Y., Harris, J., Vuckovic, J. IEEE. 2010

  View details for Web of Science ID 000290513601253

• Exciton-Polariton Laser Diodes 22nd IEEE International Semiconductor Laser Conference Schneider, C., Kim, N. Y., Rahimi-Iman, A., Nitsche, W. H., Lermer, M., Kamp, M., Reitzenstein, S., Worschech, L., Hoefling, S., Yamamoto, Y., Forchel, A. IEEE. 2010: 201–202

  View details for Web of Science ID 000287413100102

• Bose-Einstein condensation of exciton-polaritons RIVISTA DEL NUOVO CIMENTO Yamamoto, Y., Deng, H., Haug, H. 2010; 33 (10): 591-631

  View details for DOI 10.1393/ncr/i2010-10058-9

  View details for Web of Science ID 000286408700001

• Optically controlled semiconductor spin qubits for quantum information processing 141st Nobel Symposium on Qubits for Future Quantum Information Yamamoto, Y., Ladd, T. D., Press, D., Clark, S., Sanaka, K., Santori, C., Fattal, D., Fu, K. M., Hoefling, S., Reitzenstein, S., Forchel, A. IOP PUBLISHING LTD. 2009

  View details for DOI 10.1088/0031-8949/2009/T137/014010

  View details for Web of Science ID 000272834700011

• Vortex-antivortex pair dynamics in an exciton-polariton condensate NEW JOURNAL OF PHYSICS Fraser, M. D., Roumpos, G., Yamamoto, Y. 2009; 11

  View details for DOI 10.1088/1367-2630/11/11/113048

  View details for Web of Science ID 000272153200001

• Unconditional Security of Single-Photon Differential Phase Shift Quantum Key Distribution PHYSICAL REVIEW LETTERS Wen, K., Tamaki, K., Yamamoto, Y. 2009; 103 (17)

  Abstract

  In this Letter, we prove the unconditional security of the single-photon differential phase shift quantum key distribution (DPS-QKD) protocol, based on the conversion to an equivalent entanglement-based protocol. We estimate the upper bound of the phase error rate from the bit error rate, and show that the DPS-QKD protocol can generate an unconditionally secure key when the bit error rate is not greater than 4.12%. This proof is the first step to the unconditional security proof of a coherent state DPS-QKD.

  View details for DOI 10.1103/PhysRevLett.103.170503

  View details for Web of Science ID 000271164500007

  View details for PubMedID 19905739

• Indistinguishable Photons from Independent Semiconductor Nanostructures PHYSICAL REVIEW LETTERS Sanaka, K., Pawlis, A., Ladd, T. D., Lischka, K., Yamamoto, Y. 2009; 103 (5)

  Abstract

  We demonstrate quantum interference between photons generated by the radiative decay processes of excitons that are bound to isolated fluorine donor impurities in ZnSe/ZnMgSe quantum-well nanostructures. The ability to generate single photons from these devices is confirmed by autocorrelation experiments, and the indistinguishability of photons emitted from two independent nanostructures is confirmed via a Hong-Ou-Mandel dip. These results indicate that donor impurities in appropriately engineered semiconductor structures can portray atomlike homogeneity and coherence properties, potentially enabling scalable technologies for future large-scale optical quantum computers and quantum communication networks.

  View details for DOI 10.1103/PhysRevLett.103.053601

  View details for Web of Science ID 000268618300031

  View details for PubMedID 19792497

• Ultrafast Optical Spin Echo for Electron Spins in Semiconductors PHYSICAL REVIEW LETTERS Clark, S. M., Fu, K. C., Zhang, Q., Ladd, T. D., Stanley, C., Yamamoto, Y. 2009; 102 (24)

  Abstract

  Spin-based quantum computing and magnetic resonance techniques rely on the ability to measure the coherence time T(2) of a spin system. We report on the experimental implementation of all-optical spin echo to determine the T(2) time of a semiconductor electron-spin system. We use three ultrafast optical pulses to rotate spins an arbitrary angle and measure an echo signal as the time between pulses is lengthened. Unlike previous spin-echo techniques using microwaves, ultrafast optical pulses allow clean T(2) measurements of systems with dephasing times (T_{2};{*}) fast in comparison to the time scale for microwave control. This demonstration provides a step toward ultrafast optical dynamic decoupling of spin-based qubits.

  View details for DOI 10.1103/PhysRevLett.102.247601

  View details for Web of Science ID 000267197900065

  View details for PubMedID 19659047

• Signature of the microcavity exciton-polariton relaxation mechanism in the polarization of emitted light PHYSICAL REVIEW B Roumpos, G., Lai, C., Liew, T. C., Rubo, Y. G., Kavokin, A. V., Yamamoto, Y. 2009; 79 (19)

  View details for DOI 10.1103/PhysRevB.79.195310

  View details for Web of Science ID 000266501300082

• Megabits secure key rate quantum key distribution NEW JOURNAL OF PHYSICS Zhang, Q., Takesue, H., Honjo, T., Wen, K., Hirohata, T., Suyama, M., Takiguchi, Y., Kamada, H., Tokura, Y., Tadanaga, O., Nishida, Y., Asobe, M., Yamamoto, Y. 2009; 11

  View details for DOI 10.1088/1367-2630/11/4/045010

  View details for Web of Science ID 000265678400044

• Generation and application of multi-path cat states of light NEW JOURNAL OF PHYSICS Ishida, N., Ota, Y., Yamamoto, Y. 2009; 11

  View details for DOI 10.1088/1367-2630/11/3/033007

  View details for Web of Science ID 000264115200001

• Driven to perfection NATURE PHYSICS Santori, C., Yamamoto, Y. 2009; 5 (3): 173-174

  View details for DOI 10.1038/nphys1215

  View details for Web of Science ID 000264446600005

• Monolithic integration of quantum dot containing microdisk microcavities coupled to air-suspended waveguides APPLIED PHYSICS LETTERS Koseki, S., Zhang, B., De Greve, K., Yamamoto, Y. 2009; 94 (5)

  View details for DOI 10.1063/1.3078522

  View details for Web of Science ID 000263167000010

• Low-threshold ZnSe microdisk laser based on fluorine impurity bound-exciton transitions Symposium on Wide Band Gap Semiconductor Nanostructures for Optoelectronic Applications held at the 2008 E-MRS Conference Pawlis, A., Panfilova, M., Sanaka, K., Ladd, T. D., As, D. J., Lischka, K., Yamamoto, Y. ELSEVIER SCI LTD. 2009: 256–58

  View details for DOI 10.1016/j.mejo.2008.07.014

  View details for Web of Science ID 000263695100016

• Quantum interference between photons emitted by independent semiconductor single-photon devices Conference on Advanced Optical Concepts in Quantum Computing, Memory, and Communication II Sanaka, K., Pawlis, A., Ladd, T. D., Lischka, K., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2009

  View details for DOI 10.1117/12.814136

  View details for Web of Science ID 000285375700009

• Complete coherent control of a single electron spin in a quantum dot using ultrafast optical pulses Conference on Advanced Optical Concepts in Quantum Computing, Memory, and Communication II Press, D., Ladd, T. D., Zhang, B., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2009

  View details for DOI 10.1117/12.813784

  View details for Web of Science ID 000285375700001

• Megabits secure key rate quantum key distribution Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2009) Zhang, Q., Takesue, H., Honjo, T., Wen, K., Hirohata, T., Suyama, M., Takiguchi, Y., Kamada, H., Tokura, Y., Tadanaga, O., Nishida, Y., Asobe, M., Yamamoto, Y. IEEE. 2009: 2301–2302

  View details for Web of Science ID 000274751302134

• Waveguide-based single-pixel up-conversion infrared spectrometer OPTICS EXPRESS Zhang, Q., Langrock, C., Fejer, M. M., Yamamoto, Y. 2008; 16 (24): 19557-19561

  Abstract

  A periodically poled lithium niobate (PPLN) waveguide-based single-pixel up-conversion infrared spectrometer was demonstrated. Sum-frequency generation between a 1.5-microm-band scanning pump laser and a 1.3-microm-band signal generated visible radiation which was detected by a silicon single-photon detector. The up-conversion spectrometer's sensitivity was two-orders-of-magnitude higher than that of a commercial optical spectrum analyzer.

  View details for Web of Science ID 000261561900016

  View details for PubMedID 19030042

• Complete quantum control of a single quantum dot spin using ultrafast optical pulses NATURE Press, D., Ladd, T. D., Zhang, B., Yamamoto, Y. 2008; 456 (7219): 218-221

  Abstract

  A basic requirement for quantum information processing systems is the ability to completely control the state of a single qubit. For qubits based on electron spin, a universal single-qubit gate is realized by a rotation of the spin by any angle about an arbitrary axis. Driven, coherent Rabi oscillations between two spin states can be used to demonstrate control of the rotation angle. Ramsey interference, produced by two coherent spin rotations separated by a variable time delay, demonstrates control over the axis of rotation. Full quantum control of an electron spin in a quantum dot has previously been demonstrated using resonant radio-frequency pulses that require many spin precession periods. However, optical manipulation of the spin allows quantum control on a picosecond or femtosecond timescale, permitting an arbitrary rotation to be completed within one spin precession period. Recent work in optical single-spin control has demonstrated the initialization of a spin state in a quantum dot, as well as the ultrafast manipulation of coherence in a largely unpolarized single-spin state. Here we demonstrate complete coherent control over an initialized electron spin state in a quantum dot using picosecond optical pulses. First we vary the intensity of a single optical pulse to observe over six Rabi oscillations between the two spin states; then we apply two sequential pulses to observe high-contrast Ramsey interference. Such a two-pulse sequence realizes an arbitrary single-qubit gate completed on a picosecond timescale. Along with the spin initialization and final projective measurement of the spin state, these results demonstrate a complete set of all-optical single-qubit operations.

  View details for DOI 10.1038/nature07530

  View details for Web of Science ID 000261039300035

  View details for PubMedID 19005550

• Long-distance entanglement-based quantum key distribution over optical fiber OPTICS EXPRESS Honjo, T., Nam, S. W., Takesue, H., Zhang, Q., Kamada, H., Nishida, Y., Tadanaga, O., Asobe, M., Baek, B., Hadfield, R. H., Miki, S., Fujiwara, M., Sasaki, M., Wang, Z., Inoue, K., Yamamoto, Y. 2008; 16 (23): 19118-19126

  Abstract

  We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-mum telecom band, an efficient entangled photon pair source that consists of a fiber coupled periodically poled lithium niobate waveguide and ultra low loss filters, and planar lightwave circuit Mach-Zehnder interferometers (MZIs) with ultra stable operation. These characteristics enabled us to perform an entanglement-based QKD experiment over a 100-km optical fiber. In the experiment, which lasted approximately 8 hours, we successfully generated a 16 kbit sifted key with a quantum bit error rate of 6.9 % at a rate of 0.59 bits per second, from which we were able to distill a 3.9 kbit secure key.

  View details for Web of Science ID 000260866000064

  View details for PubMedID 19582004

• Ultrafast control of donor-bound electron spins with single detuned optical pulses NATURE PHYSICS Fu, K. C., Clark, S. M., Santori, C., Stanley, C. R., Holland, M. C., Yamamoto, Y. 2008; 4 (10): 780-784

  View details for DOI 10.1038/nphys1052

  View details for Web of Science ID 000259686800011

• Observation of Bogoliubov excitations in exciton-polariton condensates NATURE PHYSICS Utsunomiya, S., Tian, L., Roumpos, G., Lai, C. W., Kumada, N., Fujisawa, T., Kuwata-Gonokami, M., Loeffler, A., Hoefling, S., Forchel, A., Yamamoto, Y. 2008; 4 (9): 700-705

  View details for DOI 10.1038/nphys1034

  View details for Web of Science ID 000259686400013

• Quantum simulation of Fermi-Hubbard models in semiconductor quantum-dot arrays PHYSICAL REVIEW B Byrnes, T., Kim, N. Y., Kusudo, K., Yamamoto, Y. 2008; 78 (7)

  View details for DOI 10.1103/PhysRevB.78.075320

  View details for Web of Science ID 000259406700078

• GaAs microcavity exciton-polaritons in a trap PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Kim, N. Y., Lai, C., Utsunomiya, S., Roumpos, G., Fraser, M., Deng, H., Byrnes, T., Recher, P., Kumada, N., Fujisawa, T., Yamamoto, Y. 2008; 245 (6): 1076-1080

  View details for DOI 10.1002/pssb.200777610

  View details for Web of Science ID 000256787000011

• Distribution of Time-Energy Entanglement over 100 km fiber using superconducting single-photon detectors OPTICS EXPRESS Zhang, Q., Takesue, H., Nam, S. W., Langrock, C., Xie, X., Baek, B., Fejer, M. M., Yamamoto, Y. 2008; 16 (8): 5776-5781

  Abstract

  In this letter, we report an experimental realization of distributing entangled photon pairs over 100 km of dispersion-shifted fiber. In the experiment, we used a periodically poled lithium niobate waveguide to generate the time-energy entanglement and superconducting single-photon detectors to detect the photon pairs after 100 km. We also demonstrate that the distributed photon pairs can still be useful for quantum key distribution and other quantum communication tasks.

  View details for Web of Science ID 000255120300071

  View details for PubMedID 18542687

• Lasing of donor-bound excitons in ZnSe microdisks PHYSICAL REVIEW B Pawlis, A., Panfilova, M., As, D. J., Lischka, K., Sanaka, K., Ladd, T. D., Yamamoto, Y. 2008; 77 (15)

  View details for DOI 10.1103/PhysRevB.77.153304

  View details for Web of Science ID 000255457400007

• Generation of 10-GHz clock sequential time-bin entanglement OPTICS EXPRESS Zhang, Q., Langrock, C., Takesue, H., Xie, X., Fejer, M., Yamamoto, Y. 2008; 16 (5): 3293-3298

  Abstract

  This letter reports telecom-band sequential time-bin entangled photon-pair generation at a repetition rate of 10 GHz in periodically poled reverse-proton-exchange lithium niobate waveguides based on mode demultiplexing. With up-conversion single-photon detectors, we observed an entangled-photon-pair flux of 313 Hz and a two-photon-interference-fringe visibility of 85.32% without subtraction of accidental noise contributions.

  View details for Web of Science ID 000254121300049

  View details for PubMedID 18542417

• Strongly correlated polaritons in a two-dimensional array of photonic crystal microcavities PHYSICAL REVIEW A Na, N., Utsunomiya, S., Tian, L., Yamamoto, Y. 2008; 77 (3)

  View details for DOI 10.1103/PhysRevA.77.031803

  View details for Web of Science ID 000254541100022

• First and second order coherence of exciton-polariton condensates Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Lai, C. W., Roumpos, G., Forchel, A., Yamamoto, Y. IEEE. 2008: 2966–2967

  View details for Web of Science ID 000260498401475

• Estimation of Possible Reaction States in Metabolic Pathways using Inductive Logic Programming 22nd International Workshops on Advanced Information Networking and Applications Yamamoto, Y., Inoue, K., Doncescu, A. IEEE. 2008: 808–813

  View details for Web of Science ID 000271293300135

• Effects of direct haemoperfusion through fibres immobilizing polymyxin b and nafamostat mesilate on endotoxaemia in conscious guinea-pigs CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY Nakanowatari, Y., Nemoto, K., Hara, S., Ninomiya, N., Yamamoto, Y. 2008; 35 (1): 17-22

  Abstract

  1. Direct haemoperfusion through a network of fibres immobilizing polymyxin B (PMX-B) is used for the treatment of septic shock, but the mechanism underlying its clinical benefits remains unclear. The aims of the present study were to assess the actions of direct haemoperfusion through fibres immobilizing PMX-B (PMX-DHP) on the effects of exogenously administered endotoxin in conscious guinea-pigs and to examine the difference in the effects of heparin compared with nafamostat mesilate (NM) used as an anticoagulant. Although nafamostat is widely used in Japan, the agent cannot necessarily be used elsewhere in the world. Therefore, the study aimed to investigate and elucidate the effectiveness of NM compared with heparin. 2. Colonic motion was monitored continuously via telemetry using a force transducer attached to the taenia caecum, whereas blood pressure was monitored using a carotid artery catheter. To establish a haemoperfusion circuit in each freely moving and conscious guinea-pig, catheters were implanted in the carotid artery and the jugular vein, tunnelled subcutaneously, exteriorized at the back of the neck in contact with a lightweight tethering spring and attached to a swivel device at the top of the cage. On the day after the operation, lipopolysaccharide (LPS; Escherichia coli, O111:B4; 1 mg/kg) was administered i.v. and PMX-DHP was conducted for 2 h. Heparin (50 IU/h) or NM (0.4 mg/h) was used as the anticoagulant. Furthermore, guinea-pigs were administered a lethal dose of LPS (10 mg/kg) and the survival rate was examined for animals undergoing PMX-DHP compared with control animals. 3. In guinea-pigs treated with PMX-DHP, relaxation of colonic longitudinal muscle caused by LPS was significantly suppressed, as were decreases in blood pressure. Of the two anticoagulants used, NM was more effective than heparin. In addition, PMX-DHP significantly increased the survival rate of guinea-pigs that received potentially lethal doses of LPS. 4. In conscious and unrestrained guinea-pig endotoxaemia model, PMX-DHP significantly improved intestinal paralysis and decreases in blood pressure. These effects were augmented more by NM than by heparin when an anticoagulant was used in the perfusion process. These findings suggest that haemoperfusion using PMX and NM performed in the early stage of endotoxaemia is an effective treatment.

  View details for Web of Science ID 000251249600005

  View details for PubMedID 18047622

• Coherent zero-state and pi-state in an array of excitonpolariton condensates Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Lai, C. W., Kim, N. Y., Utsunomiya, S., Roumpos, G., Yamamoto, Y. IEEE. 2008: 2964–2965

  View details for Web of Science ID 000260498401474

• Entanglement-based BBM92 QKD experiment using superconducting single photon detectors Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Honjo, T., Nam, S. W., Takesue, H., Zhang, Q., Kamada, H., Nishida, Y., Tadanaga, O., Asobe, M., Baek, B., Hadfield, R., Miki, S., Fujiwara, M., Sasaki, M., Wang, Z., Inoue, K., Yamamoto, Y. IEEE. 2008: 3577–3578

  View details for Web of Science ID 000260498401784

• Hong-Ou-Mandel dip using photon pairs from a PPLN waveguide Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference (CLEO/QELS 2008) Zhang, Q., Takesue, H., Langrock, C., Xie, X., Fejer, M. M., Yamamoto, Y. IEEE. 2008: 2984–2985

  View details for Web of Science ID 000260498401484

• Coherent zero-state and p-state in an exciton-polariton condensate array NATURE Lai, C. W., Kim, N. Y., Utsunomiya, S., Roumpos, G., Deng, H., Fraser, M. D., Byrnes, T., Recher, P., Kumada, N., Fujisawa, T., Yamamoto, Y. 2007; 450 (7169): 529-U8

  Abstract

  The effect of quantum statistics in quantum gases and liquids results in observable collective properties among many-particle systems. One prime example is Bose-Einstein condensation, whose onset in a quantum liquid leads to phenomena such as superfluidity and superconductivity. A Bose-Einstein condensate is generally defined as a macroscopic occupation of a single-particle quantum state, a phenomenon technically referred to as off-diagonal long-range order due to non-vanishing off-diagonal components of the single-particle density matrix. The wavefunction of the condensate is an order parameter whose phase is essential in characterizing the coherence and superfluid phenomena. The long-range spatial coherence leads to the existence of phase-locked multiple condensates in an array of superfluid helium, superconducting Josephson junctions or atomic Bose-Einstein condensates. Under certain circumstances, a quantum phase difference of pi is predicted to develop among weakly coupled Josephson junctions. Such a meta-stable pi-state was discovered in a weak link of superfluid 3He, which is characterized by a 'p-wave' order parameter. The possible existence of such a pi-state in weakly coupled atomic Bose-Einstein condensates has also been proposed, but remains undiscovered. Here we report the observation of spontaneous build-up of in-phase ('zero-state') and antiphase ('pi-state') 'superfluid' states in a solid-state system; an array of exciton-polariton condensates connected by weak periodic potential barriers within a semiconductor microcavity. These in-phase and antiphase states reflect the band structure of the one-dimensional polariton array and the dynamic characteristics of metastable exciton-polariton condensates.

  View details for DOI 10.1038/nature06334

  View details for Web of Science ID 000251158500042

  View details for PubMedID 18033292

• Spatial coherence of a polariton condensate PHYSICAL REVIEW LETTERS Deng, H., Solomon, G. S., Hey, R., Ploog, K. H., Yamamoto, Y. 2007; 99 (12)

  Abstract

  We perform Young's double-slit experiment to study the spatial coherence properties of a two-dimensional dynamic condensate of semiconductor microcavity polaritons. The coherence length of the system is measured as a function of the pump rate, which confirms a spontaneous buildup of macroscopic coherence in the condensed phase. An independent measurement reveals that the position and momentum uncertainty product of the condensate is close to the Heisenberg limit. An experimental realization of such a minimum uncertainty wave packet of the polariton condensate opens a door to coherent matter-wave phenomena such as Josephson oscillation, superfluidity, and solitons in solid state condensate systems.

  View details for DOI 10.1103/PhysRevLett.99.126403

  View details for Web of Science ID 000249668000053

  View details for PubMedID 17930529

• Correlated photon-pair generation in reverse-proton-exchange PPLN waveguides with integrated mode demultiplexer at 10 GHz clock OPTICS EXPRESS Zhang, Q., Xie, X., Takesue, H., Nam, S. W., Langrock, C., Fejer, M. M., Yamamoto, Y. 2007; 15 (16): 10288-10293

  Abstract

  We report 10-ps correlated photon pair generation in periodically-poled reverse-proton-exchange lithium niobate waveguides with integrated mode demultiplexer at a wavelength of 1.5-mum and a clock of 10 GHz. Using superconducting single photon detectors, we observed a coincidence to accidental count ratio (CAR) as high as 4000. The developed photon-pair source may find broad application in quantum information systems as well as quantum entanglement experiments.

  View details for Web of Science ID 000248753100040

  View details for PubMedID 19547378

• Microcavity modified spontaneous emission of single quantum dots PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS Solomon, G. S., Pelton, M., Yamamoto, Y. 2007; 244 (8): 2792-2802

  View details for DOI 10.1002/pssb.200675619

  View details for Web of Science ID 000248712800012

• Quantum computers based on electron spins controlled by ultrafast off-resonant single optical pulses PHYSICAL REVIEW LETTERS Clark, S. M., Fu, K. C., Ladd, T. D., Yamamoto, Y. 2007; 99 (4)

  Abstract

  We describe a fast quantum computer based on optically controlled electron spins in charged quantum dots that are coupled to microcavities. This scheme uses broadband optical pulses to rotate electron spins and provide the clock signal to the system. Nonlocal two-qubit gates are performed by phase shifts induced by electron spins on laser pulses propagating along a shared waveguide. Numerical simulations of this scheme demonstrate high-fidelity single-qubit and two-qubit gates with operation times comparable to the inverse Zeeman frequency.

  View details for DOI 10.1103/PhysRevLett.99.040501

  View details for Web of Science ID 000248345800005

  View details for PubMedID 17678343

• Tomonaga-luttinger liquid features in ballistic single-walled carbon nanotubes: Conductance and shot noise PHYSICAL REVIEW LETTERS Kim, N. Y., Recher, P., Oliver, W. D., Yamamoto, Y., Kong, J., Dai, H. 2007; 99 (3)

  Abstract

  We study the electrical transport properties of well-contacted ballistic single-walled carbon nanotubes in a three-terminal configuration at low temperatures. We observe signatures of strong electron-electron interactions: the conductance exhibits bias-voltage-dependent amplitudes of quantum interference oscillation, and both the current noise and Fano factor manifest bias-voltage-dependent power-law scalings. We analyze our data within the Tomonaga-Luttinger liquid model using the nonequilibrium Keldysh formalism and find qualitative and quantitative agreement between experiment and theory.

  View details for DOI 10.1103/PhyRevLett.99.036802

  View details for Web of Science ID 000248194700038

  View details for PubMedID 17678308

• Quantum simulator for the Hubbard model with long-range Coulomb interactions using surface acoustic waves PHYSICAL REVIEW LETTERS Byrnes, T., Recher, P., Kim, N. Y., Utsunomiya, S., Yamamoto, Y. 2007; 99 (1)

  Abstract

  An experimental scheme for a quantum simulator of strongly correlated electrons is proposed. Our scheme employs electrons confined in a two-dimensional electron gas in a GaAs/AlGaAs heterojunction. Two surface acoustic waves are then induced in the substrate, creating a two-dimensional "egg-carton" potential. The dynamics of the electrons in this potential are described by a Hubbard model with long-range Coulomb interactions. Estimates of the Hubbard parameters suggest that observations of quantum phase transition phenomena are within experimental reach.

  View details for DOI 10.1103/PhysRevLett.99.016405

  View details for Web of Science ID 000247819900035

  View details for PubMedID 17678174

• Quantum key distribution over a 40-dB channel loss using superconducting single-photon detectors NATURE PHOTONICS Takesue, H., Nam, S. W., Zhang, Q., Hadfield, R. H., Honjo, T., Tamaki, K., Yamamoto, Y. 2007; 1 (6): 343-348

  View details for DOI 10.1038/nphoton.2007.75

  View details for Web of Science ID 000247344500012

• Generation and transfer of single photons on a photonic crystal chip OPTICS EXPRESS Englund, D., Faraon, A., Zhang, B., Yamamoto, Y., Vuckovic, J. 2007; 15 (9): 5550-5558

  Abstract

  We present a basic building block of a quantum network consisting of a quantum dot coupled to a source cavity, which in turn is coupled to a target cavity via a waveguide. The single photon emission from the high-Q/V source cavity is characterized by twelve-fold spontaneous emission (SE) rate enhancement, SE coupling efficiency beta ~ 0.98 into the source cavity mode, and mean wavepacket indistinguishability of ~67%. Single photons are efficiently transferred into the target cavity via the waveguide, with a target/source field intensity ratio of 0.12 +/- 0.01. This system shows great promise as a building block of future on-chip quantum information processing systems.

  View details for Web of Science ID 000246395000033

  View details for PubMedID 19532812

• Dynamics of quantum dot photonic crystal lasers APPLIED PHYSICS LETTERS Ellis, B., Fushman, I., Englund, D., Zhang, B., Yamamoto, Y., Vuckovic, J. 2007; 90 (15)

  View details for DOI 10.1063/1.2720753

  View details for Web of Science ID 000245690700002

• Photon antibunching from a single quantum-dot-microcavity system in the strong coupling regime PHYSICAL REVIEW LETTERS Press, D., Goetzinger, S., Reitzenstein, S., Hofmann, C., Loeffler, A., Kamp, M., Forchel, A., Yamamoto, Y. 2007; 98 (11)

  Abstract

  We observe antibunching in the photons emitted from a strongly coupled single quantum dot and pillar microcavity in resonance. When the quantum dot was spectrally detuned from the cavity mode, the cavity emission remained antibunched, and also anticorrelated from the quantum dot emission. Resonant pumping of the selected quantum dot via an excited state enabled these observations by eliminating the background emitters that are usually coupled to the cavity. This device demonstrates an on-demand single-photon source operating in the strong coupling regime, with a Purcell factor of 61+/-7 and quantum efficiency of 97%.

  View details for DOI 10.1103/PhysRevLett.98.117402

  View details for Web of Science ID 000244959300067

  View details for PubMedID 17501092

• Quantum simulation of spin ordering with nuclear spins in a solid-state lattice PHYSICAL REVIEW B Roumpos, G., Master, C. P., Yamamoto, Y. 2007; 75 (9)

  View details for DOI 10.1103/PhysRevB.75.094415

  View details for Web of Science ID 000245328500053

• Algorithm-based analysis of collective decoherence in quantum computation JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS Utsunomiya, S., Master, C. P., Yamamoto, Y. 2007; 24 (2): 198-208

  View details for Web of Science ID 000244281200006

• Optical quantum information science - Introduction JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS Sanders, B., Yamamoto, Y., Zeilinger, A. 2007; 24 (2)

  View details for Web of Science ID 000244281200001

• Dynamics of Quantum Dot Photonic Crystal Lasers Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference Ellis, B., Fushman, I., Englund, D., Zhang, B., Yamamoto, Y., Vuckovic, J. IEEE. 2007: 145–146

  View details for Web of Science ID 000268751000073

• Strong coupling of single quantum dots to micropillars Conference on Photonic Materials, Devices and Applications II Goetzinger, S., Press, D., Reitzenstein, S., Hofmann, K., Loeffler, A., Kamp, M., Forchel, A., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2007

  View details for DOI 10.1117/12.726311

  View details for Web of Science ID 000250171600073

• 1.5-mu m single photon counting using polarization-independent up-conversion detector OPTICS EXPRESS Takesue, H., Diamanti, E., Langrock, C., Fejer, M. M., Yamamoto, Y. 2006; 14 (26): 13067-13072

  Abstract

  We report a 1.5- mum band polarization independent single photon detector based on frequency up-conversion in periodically poled lithium niobate (PPLN) waveguides. To overcome the polarization dependence of the PPLN waveguides, we employed a polarization diversity configuration composed of two up-conversion detectors connected with a polarization beam splitter. We experimentally confirmed polarization independent single photon counting using our detector. We undertook a proof-of-principle differential phase shift quantum key distribution experiment using the detector, and confirmed that the sifted key rate and error rate remained stable when the polarization state was changed during single photon transmission.

  View details for Web of Science ID 000243144600056

  View details for PubMedID 19532202

• 100 km differential phase shift quantum key distribution experiment with low jitter up-conversion detectors OPTICS EXPRESS Diamanti, E., Takesue, H., Langrock, C., Fejer, M. M., Yamamoto, Y. 2006; 14 (26): 13073-13082

  Abstract

  We present a quantum key distribution experiment in which keys that were secure against all individual eavesdropping attacks allowed by quantum mechanics were distributed over 100 km of optical fiber. We implemented the differential phase shift quantum key distribution protocol and used low timing jitter 1.55 microm single-photon detectors based on frequency up-conversion in periodically poled lithium niobate waveguides and silicon avalanche photodiodes. Based on the security analysis of the protocol against general individual attacks, we generated secure keys at a practical rate of 166 bit/s over 100 km of fiber. The use of the low jitter detectors also increased the sifted key generation rate to 2 Mbit/s over 10 km of fiber.

  View details for Web of Science ID 000243144600057

  View details for PubMedID 19532203

• Tomonaga-Luttinger liquid correlations and Fabry-Perot interference in conductance and finite-frequency shot noise in a single-walled carbon nanotube PHYSICAL REVIEW B Recher, P., Kim, N. Y., Yamamoto, Y. 2006; 74 (23)

  View details for DOI 10.1103/PhysRevB.74.235438

  View details for Web of Science ID 000243195700126

• A gallium-nitride single-photon source operating at 200K NATURE MATERIALS Kako, S., Santori, C., Hoshino, K., Goetzinger, S., Yamamoto, Y., Arakawa, Y. 2006; 5 (11): 887-892

  Abstract

  Fundamentally secure quantum cryptography has still not seen widespread application owing to the difficulty of generating single photons on demand. Semiconductor quantum-dot structures have recently shown great promise as practical single-photon sources, and devices with integrated optical cavities and electrical-carrier injection have already been demonstrated. However, a significant obstacle for the application of commonly used III-V quantum dots to quantum-information-processing schemes is the requirement of liquid-helium cryogenic temperatures. Epitaxially grown gallium nitride quantum dots embedded in aluminium nitride have the potential for operation at much higher temperatures. Here, we report triggered single-photon emission from gallium nitride quantum dots at temperatures up to 200 K, a temperature easily reachable with thermo-electric cooling. Gallium nitride quantum dots also open a new wavelength region in the blue and near-ultraviolet portions of the spectrum for single-photon sources.

  View details for DOI 10.1038/nmat1763

  View details for Web of Science ID 000241732000023

  View details for PubMedID 17057699

• Quantum degenerate exciton-polaritons in thermal equilibrium PHYSICAL REVIEW LETTERS Deng, H., Press, D., Gotzinger, S., Solomon, G. S., Hey, R., Ploog, K. H., Yamamoto, Y. 2006; 97 (14)

  Abstract

  We study the momentum distribution and relaxation dynamics of semiconductor microcavity polaritons by angle-resolved and time-resolved spectroscopy. Above a critical pump level, the thermalization time of polaritons at positive detunings becomes shorter than their lifetime, and the polaritons form a quantum degenerate Bose-Einstein distribution in thermal equilibrium with the lattice.

  View details for DOI 10.1103/PhysRevLett.97.146402

  View details for Web of Science ID 000241057100052

  View details for PubMedID 17155273

• 10-GHz clock differential phase shift quantum key distribution experiment OPTICS EXPRESS Takesue, H., Diamanti, E., Langrock, C., Fejer, M. M., Yamamoto, Y. 2006; 14 (20): 9522-9530

  Abstract

  This paper reports the first quantum key distribution experiment implemented with a 10-GHz clock frequency. We used a 10-GHz actively mode-locked fiber laser as a source of short coherent pulses and single photon detectors based on frequency up-conversion in periodically poled lithium niobate waveguides. The use of short pulses and low-jitter upconversion detectors significantly reduced the bit errors caused by detector dark counts even after long-distance transmission of a weak coherent state pulse. We employed the differential phase shift quantum key distribution protocol, and generated sifted keys at a rate of 3.7 kbit/s over a 105 km fiber with a bit error rate of 9.7%.

  View details for Web of Science ID 000240981000069

  View details for PubMedID 19529339

• Quantum communication and information processing with quantum dots International Conference on Quantum Physics of Nature/6th European Workshop on Quantum Information Processing and Communication Yamamoto, Y. SPRINGER. 2006: 299–311

  View details for DOI 10.1007/s11128-006-0027-0

  View details for Web of Science ID 000241582300001

• Investigation of excitons bound to fluorine donors in ZnSe SEMICONDUCTOR SCIENCE AND TECHNOLOGY Pawlis, A., Sanaka, K., Gotzinger, S., Yamamoto, Y., Lischka, K. 2006; 21 (10): 1412-1415

  View details for DOI 10.1088/0268-1242/21/10/007

  View details for Web of Science ID 000242578100007

• Solid state ion trap: Lateral confinement of quantum well excitons by oscillating piezoelectric field SOLID STATE COMMUNICATIONS Na, Y. C., Yamamoto, Y. 2006; 140 (1): 28-32

  View details for DOI 10.1016/j.ssc.2006.07.027

  View details for Web of Science ID 000240894400007

• Hybrid quantum repeater based on dispersive CQED interactions between matter qubits and bright coherent light NEW JOURNAL OF PHYSICS Ladd, T. D., van Loock, P., Nemoto, K., Munro, W. J., Yamamoto, Y. 2006; 8

  View details for DOI 10.1088/1367-2630/8/9/184

  View details for Web of Science ID 000240503500005

• Millisecond spin-flip times of donor-bound electrons in GaAs PHYSICAL REVIEW B Fu, K. C., Yeo, W., Clark, S., Santori, C., Stanley, C., Holland, M. C., Yamamoto, Y. 2006; 74 (12)

  View details for DOI 10.1103/PhysRevB.74.121304

  View details for Web of Science ID 000240872500007

• Time-domain simulation of Schrodinger equation to determine the effective potential induced by an oscillating standing wave JOURNAL OF APPLIED PHYSICS Na, Y. C., Yamamoto, Y. 2006; 100 (4)

  View details for DOI 10.1063/1.2234803

  View details for Web of Science ID 000240236800143

• Hybrid quantum repeater using bright coherent light PHYSICAL REVIEW LETTERS van Loock, P., Ladd, T. D., Sanaka, K., Yamaguchi, F., Nemoto, K., Munro, W. J., Yamamoto, Y. 2006; 96 (24)

  Abstract

  We describe a quantum repeater protocol for long-distance quantum communication. In this scheme, entanglement is created between qubits at intermediate stations of the channel by using a weak dispersive light-matter interaction and distributing the outgoing bright coherent-light pulses among the stations. Noisy entangled pairs of electronic spin are then prepared with high success probability via homodyne detection and postselection. The local gates for entanglement purification and swapping are deterministic and measurement-free, based upon the same coherent-light resources and weak interactions as for the initial entanglement distribution. Finally, the entanglement is stored in a nuclear-spin-based quantum memory. With our system, qubit-communication rates approaching 100 Hz over 1280 km with fidelities near 99% are possible for reasonable local gate errors.

  View details for DOI 10.1103/PhysRevLett.96.240501

  View details for Web of Science ID 000238487900004

  View details for PubMedID 16907223

• Generation and manipulation of nonclassical light using photonic crystals 12th International Conference on Modulated Semiconductor Structures (MSS12) Vuckovic, J., Englund, D., Fattal, D., Waks, E., Yamamoto, Y. ELSEVIER SCIENCE BV. 2006: 466–70

  View details for DOI 10.1016/j.physe.2005.12.135

  View details for Web of Science ID 000237842200119

• 1.5 mu m photon-counting optical time-domain reflectometry with a single-photon detector based on upconversion in a periodically poled lithium niobate waveguide OPTICS LETTERS Diamanti, E., Langrock, C., Fejer, M. M., Yamamoto, Y., Takesue, H. 2006; 31 (6): 727-729

  Abstract

  Optical time-domain reflectometry (OTDR) is one of the most powerful tools in the characterization of optical fiber links. We demonstrate a photon-counting OTDR system at 1.5 microm with a single-photon detector, which combines frequency upconversion in a periodically poled lithium niobate waveguide and a silicon avalanche photodiode. The system exhibits high sensitivity, good spatial resolution, and short measurement time.

  View details for Web of Science ID 000235833400017

  View details for PubMedID 16544604

• Highly nonclassical photon statistics in parametric down-conversion PHYSICAL REVIEW A Waks, E., Sanders, B. C., Diamanti, E., Yamamoto, Y. 2006; 73 (3)

  View details for DOI 10.1103/PhysRevA.73.033814

  View details for Web of Science ID 000236467500174

• Simulating lattice gauge theories on a quantum computer PHYSICAL REVIEW A Byrnes, T., Yamamoto, Y. 2006; 73 (2)

  View details for DOI 10.1103/PhysRevA.73.022328

  View details for Web of Science ID 000235668100067

• Generation of photon number states NEW JOURNAL OF PHYSICS Waks, E., Diamanti, E., Yamamoto, Y. 2006; 8

  View details for DOI 10.1088/1367-2630/8/1/004

  View details for Web of Science ID 000234893200004

• Security of differential-phase-shift quantum key distribution against individual attacks PHYSICAL REVIEW A Waks, E., Takesue, H., Yamamoto, Y. 2006; 73 (1)

  View details for DOI 10.1103/PhysRevA.73.012344

  View details for Web of Science ID 000235008900073

• Differential phase shift quantum key distribution experiment over 105km fibre NEW JOURNAL OF PHYSICS Takesue, H., Diamanti, E., Honjo, T., Langrock, C., Fejer, M. M., Inoue, K., Yamamoto, Y. 2005; 7

  View details for DOI 10.1088/1367-2630/7/1/232

  View details for Web of Science ID 000233612000001

• Performance of various quantum-key-distribution systems using 1.55-mu m up-conversion single-photon detectors PHYSICAL REVIEW A Diamanti, E., Takesue, H., Honjo, T., Inoue, K., Yamamoto, Y. 2005; 72 (5)

  View details for DOI 10.1103/PhysRevA.72.052311

  View details for Web of Science ID 000233603400050

• Coherent population trapping of electron spins in a high-purity n-type GaAs semiconductor PHYSICAL REVIEW LETTERS Fu, K. M., Santori, C., Stanley, C., Holland, M. C., Yamamoto, Y. 2005; 95 (18)

  Abstract

  In high-purity n-type GaAs under a strong magnetic field, we are able to isolate a lambda system composed of two Zeeman states of neutral-donor-bound electrons and the lowest Zeeman state of bound excitons. When the two-photon detuning of this system is zero, we observe a pronounced dip in the excited-state photoluminescence, indicating the creation of the coherent population-trapped state. Our data are consistent with a steady-state three-level density-matrix model. The observation of coherent population trapping in GaAs indicates that this and similar semiconductor systems could be used for various electromagnetically induced transparency type experiments.

  View details for DOI 10.1103/PhysRevLett.95.187405

  View details for Web of Science ID 000232887400072

  View details for PubMedID 16383948

• HIV-1 infection initiates changes in the expression of a wide array of genes in U937 promonocytes and HUT78 T cells VIRUS RESEARCH Wen, W. R., Chen, S. T., Cao, Y., Zhu, Y. H., Yamamoto, Y. 2005; 113 (1): 26-35

  Abstract

  Human monocytes/macrophages (M/M) are the major targets for human immunodeficiency virus type 1 (HIV-1) infection. To characterize the global effects of acute HIV-1 infection on gene expression in M/M, the expression levels of 550 host cell RNA transcripts in U937 human promonocytes at 2-3 days after HIV-1 infection were assessed using cDNA microarray analysis and were compared to those in the infected HUT78, a CD4+ T cell line. Confirmed by semiquantitative RT-PCR, our results showed that 12 genes were up-regulated and 26 genes were down-regulated in the infected U937 cells at 2-3 days post-infection, whereas 8 genes were up-regulated and 20 genes were down-regulated in the infected HUT78 cells at 2-3 days post-infection. These genes encode a host of proteins with divergent functions in a variety of cellular processes including apoptosis (FAS, Fas ligand, PIN, HSP90beta, bcl-2, bcl-x), cell signal transduction (Ras, RGS1, IRF-1, STAT3), receptor-mediated signaling transduction (CD71, CD69, CD3delta), cell cycle and growth (c-myc, cytokines, kinase), transcriptional regulation (EWS, CREB-2), and chemotaxis (beta-chemokines, RANTES), supporting the general effects of HIV-1 infection on cells of different origin. Although most identified genes were regulated similarly in both infected cell lines, differences in gene regulation, such as c-myc, CD71, CD69, and beta-chemokines, between the two infected cell lines were also identified in this study. These differences may further our understanding of the pathogenicity of HIV and enable the discovery of novel therapeutic approach for AIDS.

  View details for DOI 10.1016/j.virusres.2005.04.002

  View details for Web of Science ID 000232022200003

  View details for PubMedID 15885842

• Photon correlation studies of single GaN quantum dots APPLIED PHYSICS LETTERS Santori, C., Gotzinger, S., Yamamoto, Y., Kako, S., Hoshino, K., Arakawa, Y. 2005; 87 (5)

  View details for DOI 10.1063/1.2006987

  View details for Web of Science ID 000230886100023

• Controlling the spontaneous emission rate of single quantum dots in a two-dimensional photonic crystal PHYSICAL REVIEW LETTERS Englund, D., Fattal, D., Waks, E., Solomon, G., Zhang, B., Nakaoka, T., Arakawa, Y., Yamamoto, Y., Vuckovic, J. 2005; 95 (1)

  Abstract

  We observe large spontaneous emission rate modification of individual InAs quantum dots (QDs) in a 2D photonic crystal with a modified, high-Q single-defect cavity. Compared to QDs in a bulk semiconductor, QDs that are resonant with the cavity show an emission rate increase of up to a factor of 8. In contrast, off-resonant QDs indicate up to fivefold rate quenching as the local density of optical states is diminished in the photonic crystal. In both cases, we demonstrate photon antibunching, showing that the structure represents an on-demand single photon source with a pulse duration from 210 ps to 8 ns. We explain the suppression of QD emission rate using finite difference time domain simulations and find good agreement with experiment.

  View details for DOI 10.1103/PhysRevLett.95.013904

  View details for Web of Science ID 000230275500032

  View details for PubMedID 16090618

• Highly efficient single-photon detection at communication wavelengths by use of upconversion in reverse-proton-exchanged periodically poled LiNbO3 waveguides OPTICS LETTERS Langrock, C., Diamanti, E., Roussev, R. V., Yamamoto, Y., Fejer, M. M., Takesue, H. 2005; 30 (13): 1725-1727

  Abstract

  Conventional single-photon detectors at communication wavelengths suffer from low quantum efficiencies and large dark counts. We present a single-photon detection system, operating at communication wavelengths, based on guided-wave frequency upconversion in a nonlinear crystal with an overall system detection efficiency (upconversion + detection) exceeding 46% at 1.56 microm. This system consists of a fiber-pigtailed reverse-proton-exchanged periodically poled LiNbO3 waveguide device in conjunction with a silicon-based single-photon counting module.

  View details for Web of Science ID 000230193000043

  View details for PubMedID 16075551

• Magnetic mesa structures fabricated by reactive ion etching with CO/NH3/Xe plasma chemistry for an all-silicon quantum computer NANOTECHNOLOGY Wang, D. F., Takahashi, A., Matsumoto, Y., Itoh, K. M., Yamamoto, Y., Ono, T., Esashi, M. 2005; 16 (6): 990-994

  View details for DOI 10.1088/0957-4484/16/6/062

  View details for Web of Science ID 000230144700062

• Optical pumping of Si-29 nuclear spins in bulk silicon at high magnetic field and liquid helium temperature PHYSICAL REVIEW B Verhulst, A. S., Rau, I. G., Yamamoto, Y., Itoh, K. M. 2005; 71 (23)

  View details for DOI 10.1103/PhysRevB.71.235206

  View details for Web of Science ID 000230276800048

• Fabrication of InAs quantum dots in AlAs/GaAs DBR pillar microcavities for single photon sources JOURNAL OF APPLIED PHYSICS Zhang, B. Y., Solomon, G. S., Pelton, M., Plant, J., Santori, C., Vuckovic, J., Yamamoto, Y. 2005; 97 (7)

  View details for DOI 10.1063/1.1882764

  View details for Web of Science ID 000228287300018

• Electrostatic force spectroscopy of near surface localized states 7th International Conference on Non-contact Atomic Force Microscopy Dana, A., Yamamoto, Y. IOP PUBLISHING LTD. 2005: S125–S133

  View details for DOI 10.1088/0957-4484/16/3/023

  View details for Web of Science ID 000228157900024

• Coherence time of decoupled nuclear spins in silicon PHYSICAL REVIEW B Ladd, T. D., Maryenko, D., Yamamoto, Y., Abe, E., Itoh, K. M. 2005; 71 (1)

  View details for DOI 10.1103/PhysRevB.71.014401

  View details for Web of Science ID 000226735100081

• Cavity-enhanced single photons from a quantum dot Conference on Physics and Simulation of Optoelectronic Devices XIII Vuckovic, J., Fattal, D., Englund, D., Waks, E., Santori, C., Solomon, G., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2005: 19–29

  View details for DOI 10.1117/12.601822

  View details for Web of Science ID 000229828500003

• 1.5 mu m photon-counting optical time domain reflectometry with a single-photon detector using up-conversion in a PPLN waveguide Conference on Lasers and Electro-Optics (CLEO) Diamanti, E., Langrock, C., Fejer, M. M., Yamamoto, Y., Takesue, H. OPTICAL SOC AMERICA. 2005: 1079–1081

  View details for Web of Science ID 000234819901105

• Generation of single photons and correlated photon pairs using InAs quantum dots Workshop on Quantum Optics for Quantum Informational Processing Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. WILEY-V C H VERLAG GMBH. 2004: 1180–88

  View details for DOI 10.1002/prop.200410188

  View details for Web of Science ID 000225072400017

• Fluctuations and noise in photonics and quantum optics: a special issue in memory of Hermann Haus JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS Abbott, D., Shapiro, J. H., Yamamoto, Y. 2004; 6 (8): S621-S622

  View details for Web of Science ID 000225565000001

• Single-photon generation with InAs quantum dots NEW JOURNAL OF PHYSICS Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. 2004; 6

  View details for DOI 10.1088/1367-2630/6/1/089

  View details for Web of Science ID 000222971800005

• Semiconductor microcavity as a spin-dependent optoelectronic device PHYSICAL REVIEW B Shelykh, I., Kavokin, K. V., Kavokin, A. V., Malpuech, G., Bigenwald, P., Deng, H., Weihs, G., Yamamoto, Y. 2004; 70 (3)

  View details for DOI 10.1103/PhysRevB.70.035320

  View details for Web of Science ID 000222996700083

• Submicrosecond correlations in photoluminescence from InAs quantum dots PHYSICAL REVIEW B Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Waks, E., Yamamoto, Y. 2004; 69 (20)

  View details for DOI 10.1103/PhysRevB.69.205324

  View details for Web of Science ID 000222095700060

• Direct observation of nonclassical photon statistics in parametric down-conversion PHYSICAL REVIEW LETTERS Waks, E., Diamanti, E., Sanders, B. C., Bartlett, S. D., Yamamoto, Y. 2004; 92 (11)

  Abstract

  We employ a high quantum efficiency photon number counter to determine the photon number distribution of the output field from a parametric down-converter. The raw photocount data directly demonstrates that the source is nonclassical by 40 standard deviations, and correcting for the quantum efficiency yields a direct observation of oscillations in the photon number distribution.

  View details for DOI 10.1103/PhysRevLett.92.113602

  View details for Web of Science ID 000220344400018

  View details for PubMedID 15089134

• Optical detection of the spin state of a single nucleus in silicon PHYSICAL REVIEW B Fu, K. M., Ladd, T. D., Santori, C., Yamamoto, Y. 2004; 69 (12)

  View details for DOI 10.1103/PhysRevB.69.125306

  View details for Web of Science ID 000221259000069

• Polariton lasing in a microcavity PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE Weihs, G., Deng, H., Snoke, D., Yamamoto, Y. 2004; 201 (4): 625-632

  View details for DOI 10.1002/pssa.200304061

  View details for Web of Science ID 000220616600006

• Entanglement formation and violation of Bell's inequality with a semiconductor single photon source PHYSICAL REVIEW LETTERS Fattal, D., Inoue, K., Vuckovic, J., Santori, C., Solomon, G. S., Yamamoto, Y. 2004; 92 (3)

  Abstract

  We report the generation of polarization-entangled photons, using a quantum dot single photon source, linear optics, and photodetectors. Two photons created independently are observed to violate Bell's inequality. The density matrix describing the polarization state of the postselected photon pairs is reconstructed and agrees well with a simple model predicting the quality of entanglement from the known parameters of the single photon source. Our scheme provides a method to create no more than one entangled photon pair per cycle after postselection, a feature useful to enhance quantum cryptography protocols based on shared entanglement.

  View details for DOI 10.1103/PhysRevLett.92.037903

  View details for Web of Science ID 000188392800061

  View details for PubMedID 14753911

• Quantum teleportation with a quantum dot single photon source PHYSICAL REVIEW LETTERS Fattal, D., Diamanti, E., Inoue, K., Yamamoto, Y. 2004; 92 (3)

  Abstract

  We report the experimental demonstration of a quantum teleportation protocol with a semiconductor single photon source. Two qubits, a target and an ancilla, each defined by a single photon occupying two optical modes (dual-rail qubit), were generated independently by the single photon source. Upon measurement of two modes from different qubits and postselection, the state of the two remaining modes was found to reproduce the state of the target qubit. In particular, the coherence between the target qubit modes was transferred to the output modes to a large extent. The observed fidelity is 80%, in agreement with the residual distinguishability between consecutive photons from the source. An improved version of this teleportation scheme using more ancillas is the building block of the recent Knill, Laflamme, and Milburn proposal for efficient linear optics quantum computation.

  View details for DOI 10.1103/PhysRevLett.92.037904

  View details for Web of Science ID 000188392800062

  View details for PubMedID 14753912

• Photon number generation with the visible light photon counter Conference on Quantum Communications and Quantum Imaging II Waks, E., Diamanti, E., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2004: 73–86

  View details for DOI 10.1117/12.561471

  View details for Web of Science ID 000225749100008

• Quantum cryptography with a single photon source Conference on Quantum Communications and Quantum Imaging Waks, E., Inoue, K., Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2004: 76–86

  View details for Web of Science ID 000189441500010

• Polariton lasing vs. photon lasing in a semiconductor microcavity PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Deng, H., Weihs, G., Snoke, D., Bloch, J., Yamamoto, Y. 2003; 100 (26): 15318-15323

  Abstract

  Nearly one decade after the first observation of Bose-Einstein condensation in atom vapors and realization of matter-wave (atom) lasers, similar concepts have been demonstrated recently for polaritons: half-matter, half-light quasiparticles in semiconductor microcavities. The half-light nature of polaritons makes polariton lasers promising as a new source of coherent and nonclassical light with extremely low threshold energy. The half-matter nature makes polariton lasers a unique test bed for many-body theories and cavity quantum electrodynamics. In this article, we present a series of experimental studies of a polariton laser, exploring its properties as a relatively dense degenerate Bose gas and comparing it to a photon laser achieved in the same structure. The polaritons have an effective mass that is twice the cavity photon effective mass, yet seven orders of magnitude less than the hydrogen atom mass; hence, they can potentially condense at temperatures seven orders of magnitude higher than those required for atom Bose-Einstein condensations. Accompanying the phase transition, a polariton laser emits coherent light but at a threshold carrier density two orders of magnitude lower than that needed for a normal photon laser in a same structure. It also is shown that, beyond threshold, the polariton population splits to a thermal equilibrium Bose-Einstein distribution at in-plane wave number k parallel > 0 and a nonequilibrium condensate at k parallel approximately 0, with a chemical potential approaching to zero. The spatial distributions and polarization characteristics of polaritons also are discussed as unique signatures of a polariton laser.

  View details for DOI 10.1073/pnas.2634328100

  View details for Web of Science ID 000187554600009

  View details for PubMedID 14673089

  View details for PubMedCentralID PMC307565

• High-efficiency photon-number detection for quantum in-formation processing IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS Waks, E., Inoue, K., Oliver, W. D., Diamanti, E., Yamamoto, Y. 2003; 9 (6): 1502-1511

  View details for DOI 10.1109/jstqe.2003.820917

  View details for Web of Science ID 000188858700008

• Noise in amplifiers JOURNAL OF LIGHTWAVE TECHNOLOGY Yamamoto, Y., Inoue, K. 2003; 21 (11): 2895-2915

  View details for DOI 10.1109/JLT.2003.816887

  View details for Web of Science ID 000187064500047

• Exciton-polariton lasing in a microcavity SEMICONDUCTOR SCIENCE AND TECHNOLOGY Weihs, G., Deng, H., Huang, R., Sugita, M., Tassone, F., Yamamoto, Y. 2003; 18 (10): S386-S394

  View details for Web of Science ID 000186246900014

• Double and single peaks in nuclear magnetic resonance spectra of natural and Si-29-enriched single-crystal silicon PHYSICAL REVIEW B Verhulst, A. S., Maryenko, D., Yamamoto, Y., Itoh, K. M. 2003; 68 (5)

  View details for DOI 10.1103/PhysRevB.68.054105

  View details for Web of Science ID 000185240100031

• The Rashba effect within the coherent scattering formalism with applications to electron quantum optics JOURNAL OF SUPERCONDUCTIVITY Oliver, W. D., Feve, G., Yamamoto, Y. 2003; 16 (4): 719-733

  View details for Web of Science ID 000184875500015

• Differential-phase-shift quantum key distribution using coherent light PHYSICAL REVIEW A Inoue, K., Waks, E., Yamamoto, Y. 2003; 68 (2)

  View details for DOI 10.1103/PhysRevA.68.022317

  View details for Web of Science ID 000185192100035

• Indistinguishable single photons from a quantum dot 2nd International Conference on Semiconductor Quantum Dots Fattal, D., Santori, C., Vuckovic, J., Solomon, G. S., Yamamoto, Y. WILEY-BLACKWELL. 2003: 305–8

  View details for DOI 10.1002/pssb.200303050

  View details for Web of Science ID 000184299800020

• Comment on "Single-mode spontaneous emission from a single quantum dot in a three-dimensional microcavity" - Solomon, Pelton, and Yamamoto reply PHYSICAL REVIEW LETTERS Solomon, G. S., Pelton, M., Yamamoto, Y. 2003; 90 (22)

  View details for DOI 10.1103/PhysRevLett.90.229702

  View details for Web of Science ID 000183381200048

• Entanglement-based quantum key distribution without an entangled-photon source PHYSICAL REVIEW A Inoue, K., Santori, C., Waks, E., Yamamoto, Y. 2003; 67 (6)

  View details for DOI 10.1103/PhysRevA.67.062319

  View details for Web of Science ID 000183915200048

• Photonic crystal microcavities for cavity quantum electrodynamics with a single quantum dot APPLIED PHYSICS LETTERS Vuckovic, J., Yamamoto, Y. 2003; 82 (15): 2374-2376

  View details for DOI 10.1063/1.1567824

  View details for Web of Science ID 000182104900002

• An efficient source of single photons: a single quantum dot in a micropost microcavity International Conference on Superlattices Nano-Structures and Nano-Devices (ICSNN-02) Pelton, M., Vuckovic, J., Solomon, G., Santori, C., Zhang, B. Y., Plant, J., Yamamoto, Y. ELSEVIER SCIENCE BV. 2003: 564–67

  View details for DOI 10.1016/S1386-9477(02)00872-X

  View details for Web of Science ID 000182700700192

• Tuning the single optical mode spontaneous emission coupling of a quantum dot in a micropost cavity 12th International Conference on Molecular Beam Epitaxy (MBE-XII) Solomon, G. S., Pelton, M., Yamamoto, Y. ELSEVIER SCIENCE BV. 2003: 737–41

  View details for DOI 10.1016/S0022-0248(02)02397-7

  View details for Web of Science ID 000182179800137

• Experimental extract and empirical formulas of refractive indices of GaAs and AlAs at high temperature by HRXRD and optical reflectivity measurement 12th International Conference on Molecular Beam Epitaxy (MBE-XII) Zhang, B. Y., Solomon, G., Weihs, G., Yamamoto, Y. ELSEVIER SCIENCE BV. 2003: 777–81

  View details for Web of Science ID 000182179800144

• Efficiency of free-energy calculations of spin lattices by spectral quantum algorithms PHYSICAL REVIEW A Master, C. P., Yamaguchi, F., Yamamoto, Y. 2003; 67 (3)

  View details for DOI 10.1103/PhysRevA.67.032311

  View details for Web of Science ID 000181965900033

• Solid-state silicon NMR quantum computer PASPS Conference 2002 Abe, E., Itoh, K. M., Ladd, T. D., Goldman, J. R., Yamaguchi, F., Yamamoto, Y. SPRINGER/PLENUM PUBLISHERS. 2003: 175–78

  View details for Web of Science ID 000182060400043

• Indistinguishable single photons from a single-quantum-dot microcavity Conference on Laser Resonators and Beam Control VI Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2003: 156–166

  View details for Web of Science ID 000184238900018

• Indistinguishable single photons for quantum information systems 6th International Conference on Quantum Communication, Measurement and Computing (QCMC 02) Santori, C., Waks, E., Inoue, K., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. RINTON PRESS, INC. 2003: 511–515

  View details for Web of Science ID 000183135800110

• High-efficiency triggered photons using single cavity mode coupling of single quantum dot emission Conference on Semiconductor Optoelectronic Devices for Lightwave Communication Solomon, G. S., Pelton, M., Santori, C., Fattal, D., Vuckovic, J., Waks, E., Inoue, K., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2003: 1–14

  View details for Web of Science ID 000188596300001

• Secure communication: Quantum cryptography with a photon turnstile NATURE Waks, E., Inoue, K., Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. 2002; 420 (6917): 762-762

  View details for DOI 10.1038/420762a

  View details for Web of Science ID 000179897300046

  View details for PubMedID 12490939

• Efficient source of single photons: A single quantum dot in a micropost microcavity PHYSICAL REVIEW LETTERS Pelton, M., Santori, C., Vuckovic, J., Zhang, B. Y., Solomon, G. S., Plant, J., Yamamoto, Y. 2002; 89 (23)

  Abstract

  We have demonstrated efficient production of triggered single photons by coupling a single semiconductor quantum dot to a three-dimensionally confined optical mode in a micropost microcavity. The efficiency of emitting single photons into a single-mode traveling wave is approximately 38%, which is nearly 2 orders of magnitude higher than for a quantum dot in bulk semiconductor material. At the same time, the probability of having more than one photon in a given pulse is reduced by a factor of 7 as compared to light with Poissonian photon statistics.

  View details for DOI 10.1103/PhysRevLett.89.233602

  View details for Web of Science ID 000179362700020

  View details for PubMedID 12485008

• Rashba effect within the coherent scattering formalism PHYSICAL REVIEW B Feve, G., Oliver, W. D., Aranzana, M., Yamamoto, Y. 2002; 66 (15)

  View details for DOI 10.1103/PhysRevB.66.155328

  View details for Web of Science ID 000179080800107

• Indistinguishable photons from a single-photon device NATURE Santori, C., Fattal, D., Vuckovic, J., Solomon, G. S., Yamamoto, Y. 2002; 419 (6907): 594-597

  Abstract

  Single-photon sources have recently been demonstrated using a variety of devices, including molecules, mesoscopic quantum wells, colour centres, trapped ions and semiconductor quantum dots. Compared with a Poisson-distributed source of the same intensity, these sources rarely emit two or more photons in the same pulse. Numerous applications for single-photon sources have been proposed in the field of quantum information, but most--including linear-optical quantum computation--also require consecutive photons to have identical wave packets. For a source based on a single quantum emitter, the emitter must therefore be excited in a rapid or deterministic way, and interact little with its surrounding environment. Here we test the indistinguishability of photons emitted by a semiconductor quantum dot in a microcavity through a Hong-Ou-Mandel-type two-photon interference experiment. We find that consecutive photons are largely indistinguishable, with a mean wave-packet overlap as large as 0.81, making this source useful in a variety of experiments in quantum optics and quantum information.

  View details for DOI 10.1038/nature01086

  View details for Web of Science ID 000178483100038

  View details for PubMedID 12374958

• Condensation of semiconductor microcavity exciton polaritons SCIENCE Deng, H., Weihs, G., Santori, C., Bloch, J., Yamamoto, Y. 2002; 298 (5591): 199-202

  Abstract

  A phase transition from a classical thermal mixed state to a quantum-mechanical pure state of exciton polaritons is observed in a GaAs multiple quantum-well microcavity from the decrease of the second-order coherence function. Supporting evidence is obtained from the observation of a nonlinear threshold behavior in the pump-intensity dependence of the emission, a polariton-like dispersion relation above threshold, and a decrease of the relaxation time into the lower polariton state. The condensation of microcavity exciton polaritons is confirmed.

  View details for Web of Science ID 000178370500058

  View details for PubMedID 12364801

• Quantum simulation of the t-J model 8th International Symposium of Advanced Physical Fields on Advanced Materials for Quantum Computing (APF8) Yamaguchi, F., Yamamoto, Y. ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. 2002: 343–45

  View details for DOI 10.1016/S0759-6036(03)00039-9

  View details for Web of Science ID 000184950500025

• Security aspects of quantum key distribution with sub-Poisson light PHYSICAL REVIEW A Waks, E., Santori, C., Yamamoto, Y. 2002; 66 (4)

  View details for DOI 10.1103/PhysRevA.66.042315

  View details for Web of Science ID 000179502200044

• Optimization of three-dimensional micropost microcavities for cavity quantum electrodynamics PHYSICAL REVIEW A Vuckovic, J., Pelton, M., Scherer, A., Yamamoto, Y. 2002; 66 (2)

  View details for DOI 10.1103/PhysRevA.66.023808

  View details for Web of Science ID 000177872600110

• Polarization-correlated photon pairs from a single quantum dot PHYSICAL REVIEW B Santori, C., Fattal, D., Pelton, M., Solomon, G. S., Yamamoto, Y. 2002; 66 (4)

  View details for DOI 10.1103/PhysRevB.66.045308

  View details for Web of Science ID 000177426400058

• Differential phase shift quantum key distribution PHYSICAL REVIEW LETTERS Inoue, K., Waks, E., Yamamoto, Y. 2002; 89 (3)

  Abstract

  A novel quantum cryptography scheme is proposed, in which a single photon is prepared in a linear superposition state of three basis kets. A photon split to three pulses is sent from Alice to Bob, where the phase difference between sequential two pulses carries bit information. Bob measures the phase difference by passive differential phase detection. This scheme is suitable for fiber transmission systems and offers a key creation efficiency higher than conventional fiber-based BB84.

  View details for DOI 10.1103/PhysRevLett.89.037902

  View details for Web of Science ID 000176599500041

  View details for PubMedID 12144419

• All-silicon quantum computer PHYSICAL REVIEW LETTERS Ladd, T. D., Goldman, J. R., Yamaguchi, F., Yamamoto, Y., Abe, E., Itoh, K. M. 2002; 89 (1)

  Abstract

  A solid-state implementation of a quantum computer composed entirely of silicon is proposed. Qubits are 29Si nuclear spins arranged as chains in a 28Si (spin-0) matrix with Larmor frequencies separated by a large magnetic field gradient. No impurity dopants or electrical contacts are needed. Initialization is accomplished by optical pumping, algorithmic cooling, and pseudo-pure state techniques. Magnetic resonance force microscopy is used for ensemble measurement.

  View details for DOI 10.1103/PhysRevLett.89.017901

  View details for Web of Science ID 000176285700049

  View details for PubMedID 12097071

• Effect of coronary stent overexpansion on lumen size and intimal hyperplasia at follow-up AMERICAN JOURNAL OF CARDIOLOGY Kuriyama, N., Kobayashi, Y., Kuroda, N., Desai, K., Yamamoto, Y., Komiyama, N., Komuro, I., Fitzgerald, P. J. 2002; 89 (11): 1297-?

  View details for Web of Science ID 000175985300012

  View details for PubMedID 12031732

• Security of quantum key distribution with entangled photons against individual attacks PHYSICAL REVIEW A Waks, E., Zeevi, A., Yamamoto, Y. 2002; 65 (5)

  View details for DOI 10.1103/PhysRevA.65.052310

  View details for Web of Science ID 000175743800050

• Exciton-polariton lasing and amplification based on exciton-exciton scattering in CdTe microcavity quantum wells PHYSICAL REVIEW B Huang, R., Yamamoto, Y., Andre, R., Bleuse, J., Muller, M., Ulmer-Tuffigo, H. 2002; 65 (16)

  View details for DOI 10.1103/PhysRevB.65.165314

  View details for Web of Science ID 000175325000078

• Time-resolved spectroscopy of multiexcitonic decay in an InAs quantum dot PHYSICAL REVIEW B Santori, C., Solomon, G. S., Pelton, M., Yamamoto, Y. 2002; 65 (7)

  View details for DOI 10.1103/PhysRevB.65.073310

  View details for Web of Science ID 000174030900017

• Three-dimensionally confined modes in micropost microcavities: Quality factors and Purcell factors IEEE JOURNAL OF QUANTUM ELECTRONICS Pelton, M., Vuckovic, J., Solomon, G. S., Scherer, A., Yamamoto, Y. 2002; 38 (2): 170-177

  View details for Web of Science ID 000173483000008

• Triggered single photons and entangled photons from a quantum dot microcavity Conference on Quantum Interference and Cryptographic Keys - Novel Physics and Advancing Technologies (QUICK) Pelton, M., Santori, C., Solomon, G. S., Benson, O., Yamamoto, Y. SPRINGER. 2002: 179–90

  View details for DOI 10.1140/epjd/e20020022

  View details for Web of Science ID 000174180500007

• Electron entanglement via a quantum dot PHYSICAL REVIEW LETTERS Oliver, W. D., Yamaguchi, F., Yamamoto, Y. 2002; 88 (3)

  Abstract

  This Letter presents a method of electron entanglement generation. The system under consideration is a single-level quantum dot with one input and two output leads. The leads are arranged such that the dot is empty, single-electron tunneling is suppressed by energy conservation, and two-electron virtual cotunneling is allowed. Such a configuration effectively filters the singlet-state portion of a two-electron input, yielding a nonlocal spin-singlet state at the output leads. Coulomb interaction mediates the entanglement generation, and, in its absence, the singlet state vanishes. This approach is a four-wave mixing process analogous to the photon entanglement generated by a chi((3)) parametric amplifier.

  View details for DOI 10.1103/PhysRevB.88.037901

  View details for Web of Science ID 000173460200042

  View details for PubMedID 11801089

• Single photons and entangled photons from a quantum dot IEEE International Electron Devices Meeting Vuckovic, J., Santori, C., Fattal, D., Pelton, M., Solomon, G. S., Zhang, B. Y., Plant, J., Yamamoto, Y. IEEE. 2002: 87–90

  View details for Web of Science ID 000185143400019

• Differential phase shift quantum key distribution Conference on Quantum Optics in Computing and Communications Inoue, K., Waks, E., Yamamoto, Y. SPIE-INT SOC OPTICAL ENGINEERING. 2002: 32–39

  View details for Web of Science ID 000179070600004

• In vivo on-line intravascular ultrasound radio-frequency signal analysis for tissue characterization of coronary atherosclerosis validated by histology of coronary atherectomy tissue specimens Komiyama, N., Courtney, B., Toyozaki, T., Yokoyama, M., Yamamoto, Y., Komuro, I. LIPPINCOTT WILLIAMS & WILKINS. 2001: 591–91

  View details for Web of Science ID 000171895002773

• Single-mode spontaneous emission from a single quantum dot in a three-dimensional microcavity PHYSICAL REVIEW LETTERS Solomon, G. S., Pelton, M., Yamamoto, Y. 2001; 86 (17): 3903-3906

  Abstract

  The spontaneous emission from an isolated semiconductor quantum dot state has been coupled with high efficiency to a single, polarization-degenerate cavity mode. The InAs quantum dot is epitaxially formed and embedded in a planar epitaxial microcavity, which is processed into a post of submicron diameter. The single quantum dot spontaneous emission lifetime is reduced from the noncavity value of 1.3 ns to 280 ps, resulting in a single-mode spontaneous emission coupling efficiency of 78%.

  View details for Web of Science ID 000168338300052

  View details for PubMedID 11329353

• Triggered single photons from a quantum dot PHYSICAL REVIEW LETTERS Santori, C., Pelton, M., Solomon, G., Dale, Y., Yamamoto, E. 2001; 86 (8): 1502-1505

  Abstract

  We demonstrate a new method for generating triggered single photons. After a laser pulse generates excitons inside a single quantum dot, electrostatic interactions between them and the resulting spectral shifts allow a single emitted photon to be isolated. Correlation measurements show a reduction of the two-photon probability to 0.12 times the value for Poisson light. Strong antibunching persists when the emission is saturated. The emitted photons are also polarized.

  View details for Web of Science ID 000167010000027

  View details for PubMedID 11290178

• Lasing and squeezing of composite bosons in a semiconductor microcavity PHYSICAL REVIEW A Tassone, F., Yamamoto, Y. 2000; 62 (6)

  View details for Web of Science ID 000165697200104

• Comment on "generation of phase states by two-photon absorption" - Ezaki et al. reply PHYSICAL REVIEW LETTERS Ezaki, H., Hanamura, E., Yamamoto, Y. 2000; 85 (5): 1137-1137

  View details for Web of Science ID 000088457000060

• Magnet designs for a crystal-lattice quantum computer APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Goldman, J. R., Ladd, T. D., Yamaguchi, F., Yamamoto, Y. 2000; 71 (1): 11-17

  View details for Web of Science ID 000088498500003

• Quantum point contacts in a density-tunable two-dimensional electron gas JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS Nuttinck, S., HASHIMOTO, K., Miyashita, S., Saku, T., Yamamoto, Y., Hirayama, Y. 2000; 39 (7A): L655-L657

  View details for Web of Science ID 000088393200005

• Simultaneous Coulomb blockade for electrons and holes in p-n junctions: observation of Coulomb staircase and turnstile operation PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES Benson, O., Kim, J., Kan, H., Yamamoto, Y. 2000; 8 (1): 5-12

  View details for Web of Science ID 000088524900002

• Decoherence in crystal lattice quantum computation APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Ladd, T. D., Goldman, J. R., Yamaguchi, F., Yamamoto, Y. 2000; 71 (1): 27-36

  View details for Web of Science ID 000088498500006

• Semiconductor physics - Half-matter, half-light amplifier NATURE Yamamoto, Y. 2000; 405 (6787): 629-630

  View details for Web of Science ID 000087465800029

• Efficient implementation of coupled logic gates for quantum computation PHYSICAL REVIEW A Leung, D. W., Chuang, I. L., Yamaguchi, F., Yamamoto, Y. 2000; 61 (4)

  View details for Web of Science ID 000086313300032

• Regulated and entangled photons from a single quantum Dot Physical review letters Benson, O., Santori, C., Pelton, M., Yamamoto, Y. 2000; 84 (11): 2513-6

  Abstract

  We propose a new method of generating nonclassical optical field states. The method uses a semiconductor device, which consists of a single quantum dot as active medium embedded in a p- i- n junction and surrounded by a microcavity. Resonant tunneling of electrons and holes into the quantum dot ground states, together with the Pauli exclusion principle, produce regulated single photons or regulated pairs of photons. We propose that this device also has the unique potential to generate pairs of entangled photons at a well-defined repetition rate.

  View details for PubMedID 11018923

• Stimulated emission of excitons into polaritons in a semiconductor microcavity post 6th International Conference on Optics of Excitons in Confined Systems (OECS-6) Tassone, F., Yamamoto, Y. WILEY-BLACKWELL. 2000: 119–28

  View details for Web of Science ID 000086440500023

• Hanbury Brown and Twiss-type experiment with electrons SCIENCE Oliver, W. D., Kim, J., Liu, R. C., Yamamoto, Y. 1999; 284 (5412): 299-301

  Abstract

  Fermion anti-bunching was directly observed by measuring the cross-covariance of the current fluctuations of partitioned electrons. A quantum point contact was used to inject single-mode electrons into a mesoscopic electron beam splitter device. The beam splitter output currents showed negative cross-covariance, indicating that the electrons arrived individually at the beam splitter and were randomly partitioned into two output channels. As the relative time delay between the outputs was changed, the observed ringing in the cross-covariance was consistent with the bandwidths used to monitor the fluctuations. The result demonstrates a fermion complement to the Hanbury Brown and Twiss experiment for photons.

  View details for Web of Science ID 000079636400037

• Signs of quantum statistical effects in electron collision 12th International Conference on Electronic Properties of 2-Dimensional Systems Liu, R. C., Yamamoto, Y., Tarucha, S. ELSEVIER SCIENCE BV. 1998: 152–156

  View details for Web of Science ID 000074919400034

• Quantum interference in electron collision NATURE Liu, R. C., Odom, B., Yamamoto, Y., Tarucha, S. 1998; 391 (6664): 263-265

  View details for Web of Science ID 000071484400043

• Gravitational wave detection using dual input Michelson interferometer PHYSICS LETTERS A Inoue, S., Yamamoto, Y. 1997; 236 (3): 183-187

  View details for Web of Science ID A1997YJ77100004

• Longitudinal-mode-partition noise and amplitude squeezing in semiconductor lasers JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS Inoue, S., Lathi, S., Yamamoto, Y. 1997; 14 (11): 2761-2766

  View details for Web of Science ID A1997YF41100001

• Inhibition of elastic and inelastic scattering by the Pauli exclusion principle: Suppression mechanism for mesoscopic partition noise SOLID STATE COMMUNICATIONS Liu, R. C., Eastman, P., Yamamoto, Y. 1997; 102 (11): 785-789

  View details for Web of Science ID A1997XA61400003

• Longitudinal-mode-partition noise in a semiconductor-laser-based interferometer OPTICS LETTERS Inoue, S., Yamamoto, Y. 1997; 22 (5): 328-330

  Abstract

  We observed a periodic intensity-noise variation in the output of a Mach-Zehnder interferometer as we changed the arm-length difference in the range of several millimeters. We found that the period of the variation coincided with that expected for the longitudinal-mode separation of the semiconductor laser. The origin of the huge excess noise of a bright fringe (approximately 30 dB above the shot-noise level) was the longitudinal-mode-partition noise that was due to the selective destructive interference of side modes.

  View details for Web of Science ID A1997WJ76500025

  View details for PubMedID 18183191

• Simulations of partition noise suppression NATO Advanced Study Institute on Quantum Transport in Semiconductor Submicron Structures Liu, R. C., Eastman, P., Yamamoto, Y. SPRINGER. 1996: 365–374

  View details for Web of Science ID A1996BH46P00019

• CONDUCTANCE DEPENDENT SUPPRESSION OF CURRENT PARTITION NOISE IN MESOSCOPIC ELECTRON BRANCHING CIRCUITS PHYSICA B-CONDENSED MATTER Liu, R. C., Yamamoto, Y. 1995; 210 (1): 37-42

  View details for Web of Science ID A1995QV90100003

• Partition noise in electron transport NATO Advanced Research Workshop on Submicron Quantum Dynamics Liu, R. C., Yamamoto, Y. KLUWER ACADEMIC PUBL. 1995: 427–442

  View details for Web of Science ID A1995BE41M00033

• SUB-SHOT-NOISE INTERFEROMETRY WITH AMPLITUDE SQUEEZED LIGHT FROM A SEMICONDUCTOR LASER Conference on Laser Frequency Stabilization and Noise Reduction/Photonics West 95 Inoue, S., BJORK, G., Yamamoto, Y. SPIE - INT SOC OPTICAL ENGINEERING. 1995: 99–106

  View details for Web of Science ID A1995BC98U00010

• NYQUIST NOISE IN THE TRANSITION FROM MESOSCOPIC TO MACROSCOPIC TRANSPORT PHYSICAL REVIEW B Liu, R. C., Yamamoto, Y. 1994; 50 (23): 17411-17414

  View details for Web of Science ID A1994PZ82500071

• SUPPRESSION OF QUANTUM PARTITION NOISE IN MESOSCOPIC ELECTRON BRANCHING CIRCUITS PHYSICAL REVIEW B Liu, R. C., Yamamoto, Y. 1994; 49 (15): 10520-10532

  View details for Web of Science ID A1994NJ75600054