Bio
Monika Schleier-Smith is an Associate Professor in the Physics Department at Stanford University. She received her Ph.D. from the Massachusetts Institute of Technology, following undergraduate studies at Harvard University, and subsequently pursued postdoctoral research at the LMU Munich and Max Planck Institute of Quantum Optics. Her current research centers on advancing optical control of interactions among laser-cooled atoms, with an eye towards applications in quantum simulation, metrology, and computation. She has pioneered techniques and ideas for simulating phenomena of condensed-matter physics and quantum gravity using tools of atomic physics, and developed protocols in quantum control for entanglement-enhanced sensing.
Administrative Appointments
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Executive Committee Member, Q-FARM, Stanford-SLAC Quantum Science and Engineering Initiative (2019 - Present)
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Faculty Senator, Stanford University (2020 - 2022)
Honors & Awards
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Fellow, American Physical Society (2021)
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I. I. Rabi Prize in Atomic, Molecular, and Optical Physics, American Physical Society (2021)
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MacArthur Fellowship, MacArthur Foundation (2020)
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Presidential Early Career Award for Scientists and Engineers (PECASE), Department of Defense (2019)
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NSF CAREER Award, National Science Foundation (2018)
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Cottrell Scholar Award, Research Corporation (2017)
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Hellman Fellowship, Hellman Fellows Fund (2015)
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AFOSR Young Investigator Award, Air Force Office of Scientific Research (2014)
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Alfred P. Sloan Research Fellowship, Alfred P. Sloan Foundation (2014)
Boards, Advisory Committees, Professional Organizations
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Member-at-Large of the Executive Committee, Division of Atomic, Molecular, and Optical Physics (DAMOP), American Physical Society (APS) (2020 - 2023)
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Member of the Board of Directors, Fannie and John Hertz Foundation (2019 - 2022)
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Editorial Board Member, PRX Quantum (2020 - 2023)
Professional Education
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Ph.D., Massachusetts Institute of Technology, Physics (2011)
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A.B., Harvard University, Chemistry & Physics, Mathematics (2005)
Current Research and Scholarly Interests
In between the few-particle realm where we have mastered quantum mechanics and the macroscopic domain describable by classical physics, there lies a broad swath of territory where quantum effects are relevant but still largely out of our control and partly beyond our comprehension. This territory includes metrological instruments whose precision is limited by the quantum projection noise of millions of atoms; and materials whose bulk properties emerge from many-body interactions intractable to simulation on classical computers. Professor Schleier-Smith’s research aims to advance our control and understanding of many-particle quantum systems by engineering new quantum states and Hamiltonians with ensembles of laser-cooled atoms.
2024-25 Courses
- Electricity, Magnetism, and Optics
PHYSICS 23 (Win) -
Independent Studies (3)
- Independent Research and Study
PHYSICS 190 (Aut, Win, Spr, Sum) - Research
PHYSICS 490 (Aut, Win, Spr, Sum) - Senior Thesis Research
PHYSICS 205 (Aut, Win, Spr, Sum)
- Independent Research and Study
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Prior Year Courses
2023-24 Courses
- Electricity, Magnetism, and Optics
PHYSICS 23 (Win)
2021-22 Courses
- Atoms, Fields and Photons
APPPHYS 203 (Aut) - Quantum Information: Visions and Emerging Technologies
PHYSICS 14N (Spr)
- Electricity, Magnetism, and Optics
Stanford Advisees
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Doctoral Dissertation Reader (AC)
Sam Carman, Noah Huffman, Kevin Multani, Hunter Swan, Kangning Yang -
Postdoctoral Faculty Sponsor
Philipp Kunkel, Shankari Rajagopal, Lin Xin -
Doctoral Dissertation Advisor (AC)
Sam Cohen, Merrick Ho, Jonathan Jeffrey, Gabriel Moreau, Nolan Peard, Michelle Wu, Tony Zhang, Ocean Zhou -
Postdoctoral Research Mentor
Shankari Rajagopal
All Publications
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Graph states of atomic ensembles engineered by photon-mediated entanglement
NATURE PHYSICS
2024
View details for DOI 10.1038/s41567-024-02407-1
View details for Web of Science ID 001176316000001
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Spin Squeezing by Rydberg Dressing in an Array of Atomic Ensembles.
Physical review letters
2023; 131 (6): 063401
Abstract
We report on the creation of an array of spin-squeezed ensembles of cesium atoms via Rydberg dressing, a technique that offers optical control over local interactions between neutral atoms. We optimize the coherence of the interactions by a stroboscopic dressing sequence that suppresses super-Poissonian loss. We thereby prepare squeezed states of N=200 atoms with a metrological squeezing parameter ξ^{2}=0.77(9) quantifying the reduction in phase variance below the standard quantum limit. We realize metrological gain across three spatially separated ensembles in parallel, with the strength of squeezing controlled by the local intensity of the dressing light. Our method can be applied to enhance the precision of tests of fundamental physics based on arrays of atomic clocks and to enable quantum-enhanced imaging of electromagnetic fields.
View details for DOI 10.1103/PhysRevLett.131.063401
View details for PubMedID 37625064
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Programmable interactions and emergent geometry in an arrayof atom clouds.
Nature
1800; 600 (7890): 630-635
Abstract
Interactions govern the flow of information and the formation of correlations between constituents of many-body quantum systems, dictating phases of matter found in nature and forms of entanglement generated in the laboratory. Typical interactions decay with distance and thus produce a network of connectivity governed by geometry-such as the crystalline structure of a material or the trapping sites of atoms in a quantum simulator1,2. However, many envisioned applications in quantum simulation and computation require more complex coupling graphs including non-local interactions, which feature in models of information scrambling in black holes3-6 and mappings of hard optimization problems onto frustrated classical magnets7-11. Here we describe the realization of programmable non-local interactions in an array of atomic ensembles within an optical cavity, in which photons carry information between atomic spins12-19. By programming the distance dependence of the interactions, we access effective geometries for which the dimensionality, topology and metric are entirely distinct from the physical geometry of the array. As examples, we engineer an antiferromagnetic triangular ladder, a Mobius strip with sign-changing interactions and a treelike geometry inspired by concepts of quantum gravity5,20-22. The tree graph constitutes a toy model of holographic duality21,22, in which the quantum system lies on the boundary of a higher-dimensional geometry that emerges from measured correlations23. Our work provides broader prospects for simulating frustrated magnets and topological phases24, investigating quantum optimization paradigms10,11,25,26 and engineering entangled resource states for sensing and computation27,28.
View details for DOI 10.1038/s41586-021-04156-0
View details for PubMedID 34937894
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Number Partitioning With Grover's Algorithm in Central Spin Systems
PRX QUANTUM
2021; 2 (2)
View details for DOI 10.1103/PRXQuantum.2.020319
View details for Web of Science ID 000674719600001
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Protecting Spin Coherence in a Tunable Heisenberg Model
PHYSICAL REVIEW LETTERS
2020; 125 (6)
View details for DOI 10.1103/PhysRevLett.125.060402
View details for Web of Science ID 000554827700002
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Transverse-Field Ising Dynamics in a Rydberg-Dressed Atomic Gas
PHYSICAL REVIEW LETTERS
2020; 124 (6)
View details for DOI 10.1103/PhysRevLett.124.063601
View details for Web of Science ID 000513240600002
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Integrable and Chaotic Dynamics of Spins Coupled to an Optical Cavity
PHYSICAL REVIEW X
2019; 9 (4)
View details for DOI 10.1103/PhysRevX.9.041011
View details for Web of Science ID 000490174600001
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Treelike Interactions and Fast Scrambling with Cold Atoms
PHYSICAL REVIEW LETTERS
2019; 123 (13)
View details for DOI 10.1103/PhysRevLett.123.130601
View details for Web of Science ID 000487744600001
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Photon-Mediated Spin-Exchange Dynamics of Spin-1 Atoms
PHYSICAL REVIEW LETTERS
2019; 122 (1)
View details for DOI 10.1103/PhysRevLett.122.010405
View details for Web of Science ID 000455368500002
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Painting Nonclassical States of Spin or Motion with Shaped Single Photons
PHYSICAL REVIEW LETTERS
2018; 121 (12)
View details for DOI 10.1103/PhysRevLett.121.123602
View details for Web of Science ID 000444961000001
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Floquet Symmetry-Protected Topological Phases in Cold-Atom Systems
PHYSICAL REVIEW LETTERS
2017; 119 (12): 123601
Abstract
We propose and analyze two distinct routes toward realizing interacting symmetry-protected topological (SPT) phases via periodic driving. First, we demonstrate that a driven transverse-field Ising model can be used to engineer complex interactions which enable the emulation of an equilibrium SPT phase. This phase remains stable only within a parametric time scale controlled by the driving frequency, beyond which its topological features break down. To overcome this issue, we consider an alternate route based upon realizing an intrinsically Floquet SPT phase that does not have any equilibrium analog. In both cases, we show that disorder, leading to many-body localization, prevents runaway heating and enables the observation of coherent quantum dynamics at high energy densities. Furthermore, we clarify the distinction between the equilibrium and Floquet SPT phases by identifying a unique micromotion-based entanglement spectrum signature of the latter. Finally, we propose a unifying implementation in a one-dimensional chain of Rydberg-dressed atoms and show that protected edge modes are observable on realistic experimental time scales.
View details for PubMedID 29341658
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Measuring the scrambling of quantum information
PHYSICAL REVIEW A
2016; 94 (4)
View details for DOI 10.1103/PhysRevA.94.040302
View details for Web of Science ID 000390069700001
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Bloch state tomography using Wilson lines
SCIENCE
2016; 352 (6289): 1094-1097
Abstract
Topology and geometry are essential to our understanding of modern physics, underlying many foundational concepts from high-energy theories, quantum information, and condensed-matter physics. In condensed-matter systems, a wide range of phenomena stem from the geometry of the band eigenstates, which is encoded in the matrix-valued Wilson line for general multiband systems. Using an ultracold gas of rubidium atoms loaded in a honeycomb optical lattice, we realize strong-force dynamics in Bloch bands that are described by Wilson lines and observe an evolution in the band populations that directly reveals the band geometry. Our technique enables a full determination of band eigenstates, Berry curvature, and topological invariants, including single- and multiband Chern and Z₂ numbers.
View details for DOI 10.1126/science.aad5812
View details for Web of Science ID 000376480800037
View details for PubMedID 27230376
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Approaching the Heisenberg Limit without Single-Particle Detection
PHYSICAL REVIEW LETTERS
2016; 116 (5)
View details for DOI 10.1103/PhysRevLett.116.053601
View details for Web of Science ID 000369491700004
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An Aharonov-Bohm interferometer for determining Bloch band topology
SCIENCE
2015; 347 (6219): 288-292
Abstract
The geometric structure of a single-particle energy band in a solid is fundamental for a wide range of many-body phenomena and is uniquely characterized by the distribution of Berry curvature over the Brillouin zone. We realize an atomic interferometer to measure Berry flux in momentum space, in analogy to an Aharonov-Bohm interferometer that measures magnetic flux in real space. We demonstrate the interferometer for a graphene-type hexagonal optical lattice loaded with bosonic atoms. By detecting the singular π Berry flux localized at each Dirac point, we establish the high momentum resolution of this interferometric technique. Our work forms the basis for a general framework to fully characterize topological band structures.
View details for DOI 10.1126/science.1259052
View details for Web of Science ID 000347915300040
View details for PubMedID 25525160
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Orientation-Dependent Entanglement Lifetime in a Squeezed Atomic Clock
PHYSICAL REVIEW LETTERS
2010; 104 (25)
Abstract
We study experimentally the application of a class of entangled states, squeezed spin states, to the improvement of atomic-clock precision. In the presence of anisotropic noise, the entanglement lifetime is strongly dependent on squeezing orientation. We measure the Allan deviation spectrum of a clock operated with a phase-squeezed input state. For averaging times up to 50 s the squeezed clock achieves a given precision 2.8(3) times faster than a clock operating at the standard quantum limit.
View details for DOI 10.1103/PhysRevLett.104.250801
View details for Web of Science ID 000279178900001
View details for PubMedID 20867356
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Implementation of Cavity Squeezing of a Collective Atomic Spin
PHYSICAL REVIEW LETTERS
2010; 104 (7)
Abstract
We squeeze unconditionally the collective spin of a dilute ensemble of laser-cooled 87Rb atoms using their interaction with a driven optical resonator. The shape and size of the resulting spin uncertainty region are well described by a simple analytical model [M. H. Schleier-Smith, I. D. Leroux, and V. Vuletić, arXiv:0911.3936 [Phys. Rev. A (to be published)]] through 2 orders of magnitude in the effective interaction strength, without free parameters. We deterministically generate states with up to 5.6(6) dB of metrologically relevant spin squeezing on the canonical 87Rb hyperfine clock transition.
View details for DOI 10.1103/PhysRevLett.104.073602
View details for Web of Science ID 000274664500021
View details for PubMedID 20366881
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States of an Ensemble of Two-Level Atoms with Reduced Quantum Uncertainty
PHYSICAL REVIEW LETTERS
2010; 104 (7)
Abstract
We generate entangled states of an ensemble of 5x10{4} 87Rb atoms by optical quantum nondemolition measurement. The resonator-enhanced measurement leaves the atomic ensemble, prepared in a superposition of hyperfine clock levels, in a squeezed spin state. By comparing the resulting reduction of quantum projection noise [up to 8.8(8) dB] with the concomitant reduction of coherence, we demonstrate a clock input state with spectroscopic sensitivity 3.0(8) dB beyond the standard quantum limit.
View details for DOI 10.1103/PhysRevLett.104.073604
View details for Web of Science ID 000274664500023
View details for PubMedID 20366883
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Degradation of Ta2O5 / SiO2 dielectric cavity mirrors in ultra-high vacuum
OPTICS EXPRESS
2023; 31 (24): 39670-39680
Abstract
In order for optical cavities to enable strong light-matter interactions for quantum metrology, networking, and scalability in quantum computing systems, their mirrors must have minimal losses. However, high-finesse dielectric cavity mirrors can degrade in ultra-high vacuum (UHV), increasing the challenges of upgrading to cavity-coupled quantum systems. We observe the optical degradation of high-finesse dielectric optical cavity mirrors after high-temperature UHV bake in the form of a substantial increase in surface roughness. We provide an explanation of the degradation through atomic force microscopy (AFM), X-ray fluorescence (XRF), selective wet etching, and optical measurements. We find the degradation is explained by oxygen reduction in Ta2O5 followed by growth of tantalum sub-oxide defects with height to width aspect ratios near ten. We discuss the dependence of mirror loss on surface roughness and finally give recommendations to avoid degradation to allow for quick adoption of cavity-coupled systems.
View details for DOI 10.1364/OE.504858
View details for Web of Science ID 001125056900007
View details for PubMedID 38041283
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Solving a puzzle with atomic qubits.
Science (New York, N.Y.)
2022; 376 (6598): 1155-1156
Abstract
A quantum com puter makes light work of the maximum independent set problem.
View details for DOI 10.1126/science.abq3754
View details for PubMedID 35679424
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Measure in circles
NATURE PHYSICS
2022; 18 (2): 124-125
View details for DOI 10.1038/s41567-021-01500-z
View details for Web of Science ID 000755220000005
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Quantum Simulators: Architectures and Opportunities
PRX QUANTUM
2021; 2 (1)
View details for DOI 10.1103/PRXQuantum.2.017003
View details for Web of Science ID 000674685900003
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Transverse-Field Ising Dynamics in a Rydberg-Dressed Atomic Gas.
Physical review letters
2020; 124 (6): 063601
Abstract
We report on the realization of long-range Ising interactions in a cold gas of cesium atoms by Rydberg dressing. The interactions are enhanced by coupling to Rydberg states in the vicinity of a Förster resonance. We characterize the interactions by measuring the mean-field shift of the clock transition via Ramsey spectroscopy, observing one-axis twisting dynamics. We furthermore emulate a transverse-field Ising model by periodic application of a microwave field and detect dynamical signatures of the paramagnetic-ferromagnetic phase transition. Our results highlight the power of optical addressing for achieving local and dynamical control of interactions, enabling prospects ranging from investigating Floquet quantum criticality to producing tunable-range spin squeezing.
View details for DOI 10.1103/PhysRevLett.124.063601
View details for PubMedID 32109106
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Spectrum, Landau-Zener theory and driven-dissipative dynamics of a staircase of photons
NEW JOURNAL OF PHYSICS
2019; 21
View details for DOI 10.1088/1367-2630/aaf825
View details for Web of Science ID 000455842800005
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Photon-mediated spin-mixing dynamics
SPIE-INT SOC OPTICAL ENGINEERING. 2019
View details for DOI 10.1117/12.2515795
View details for Web of Science ID 000466478500031
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Squeezing out higher precision.
Science (New York, N.Y.)
2019; 364 (6446): 1137–38
View details for DOI 10.1126/science.aax0143
View details for PubMedID 31221847
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One- and two-axis squeezing of atomic ensembles in optical cavities
NEW JOURNAL OF PHYSICS
2017; 19
View details for DOI 10.1088/1367-2630/aa8438
View details for Web of Science ID 000424942700001
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Advantages of Interaction-Based Readout for Quantum Sensing
SPIE-INT SOC OPTICAL ENGINEERING. 2017
View details for DOI 10.1117/12.2257033
View details for Web of Science ID 000417339300010
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Editorial: Hybridizing Quantum Physics and Engineering.
Physical review letters
2016; 117 (10): 100001-?
View details for DOI 10.1103/PhysRevLett.117.100001
View details for PubMedID 27636456
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Dynamic optical superlattices with topological bands
PHYSICAL REVIEW A
2014; 89 (5)
View details for DOI 10.1103/PhysRevA.89.051605
View details for Web of Science ID 000338036000001
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Generating entangled spin states for quantum metrology by single-photon detection
PHYSICAL REVIEW A
2013; 88 (6)
View details for DOI 10.1103/PhysRevA.88.063802
View details for Web of Science ID 000328567900011
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Unitary cavity spin squeezing by quantum erasure
PHYSICAL REVIEW A
2012; 85 (1)
View details for DOI 10.1103/PhysRevA.85.013803
View details for Web of Science ID 000298860400019
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Optomechanical Cavity Cooling of an Atomic Ensemble
PHYSICAL REVIEW LETTERS
2011; 107 (14)
Abstract
We demonstrate cavity sideband cooling of a single collective motional mode of an atomic ensemble down to a mean phonon occupation number ⟨n⟩(min)=2.0(-0.3)(+0.9). Both ⟨n⟩(min) and the observed cooling rate are in good agreement with an optomechanical model. The cooling rate constant is proportional to the total photon scattering rate by the ensemble, demonstrating the cooperative character of the light-emission-induced cooling process. We deduce fundamental limits to cavity cooling either the collective mode or, sympathetically, the single-atom degrees of freedom.
View details for DOI 10.1103/PhysRevLett.107.143005
View details for Web of Science ID 000295328200003
View details for PubMedID 22107191
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Squeezing the collective spin of a dilute atomic ensemble by cavity feedback
PHYSICAL REVIEW A
2010; 81 (2)
View details for DOI 10.1103/PhysRevA.81.021804
View details for Web of Science ID 000275072500022
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A linear AC trap for polar molecules in their ground state
JOURNAL OF PHYSICAL CHEMISTRY A
2007; 111 (31): 7411-7419
Abstract
A linear AC trap for polar molecules in high-field seeking states has been devised and implemented, and its characteristics have been investigated both experimentally and theoretically. The trap is loaded with slow 15ND3 molecules in their ground state (para-ammonia) from a Stark decelerator. The trap's geometry offers optimal access as well as improved loading. We present measurements of the dependence of the trap's performance on the switching frequency, which exhibit a characteristic structure due to nonlinear resonance effects. The molecules are found to oscillate in the trap under the influence of the trapping forces, which were analyzed using 3D numerical simulations. On the basis of expansion measurements, molecules with a velocity and a position spread of 2.1 m/s and 0.4 mm, respectively, are still accepted by the trap. This corresponds to a temperature of 2.0 mK. From numerical simulations, we find the phase-space volume that can be confined by the trap (the acceptance) to be 50 mm3 (m/s)3.
View details for DOI 10.1021/jp070902n
View details for Web of Science ID 000248478700021
View details for PubMedID 17566990
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Nanotube-substrate interactions: Distinguishing carbon nanotubes by the helical angle
PHYSICAL REVIEW LETTERS
2004; 92 (8)
Abstract
We investigate the interaction of a carbon nanotube with a graphite substrate, using an interlayer potential that explicitly treats the registry dependence of the interaction. The carbon-carbon bond lengths in nanotubes differ slightly from those in flat graphite, so that the naively commensurate angular orientations for the tube with respect to the substrate lattice are destroyed. The interaction of a one-dimensional tube with a two-dimensional substrate then leads to an unusual registry phenomenon not visible in standard layer-on-layer growth: the system develops favorable orientations which clearly are incommensurate.
View details for DOI 10.1103/PhysRevLett.92.085503
View details for Web of Science ID 000189266100028
View details for PubMedID 14995788