Stanford University
Showing 301-400 of 402 Results
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Eva Silverstein
Wells Family Director of the Stanford Institute for Theoretical Physics and Professor of Physics
BioProfessor Silverstein conducts research in theoretical physics -- particularly gravitation and cosmology, as well as recently developing new methods and applications for machine learning.
What are the basic degrees of freedom and interactions underlying gravitational and particle physics? What is the mechanism behind the initial seeds of structure in the universe, and how can we test it using cosmological observations? Is there a holographic framework for cosmology that applies throughout the history of the universe, accounting for the emergent effects of horizons and singularities? What new phenomena arise in quantum field theory in generic conditions such as finite density, temperature, or in time dependent backgrounds?
Professor Silverstein attacks basic problems in several areas of theoretical physics. She develops concrete and testable mechanisms for cosmic inflation, accounting for its sensitivity to very high energy physics. This has led to a fruitful interface with cosmic microwave background research, contributing to a more systematic analysis of its observable phenomenology.
Professor Silverstein also develops mechanisms for stabilizing the extra dimensions of string theory to model the accelerated expansion of the universe. In addition, Professor Silverstein develops methods to address questions of quantum gravity, such as singularity resolution and the physics of black hole and cosmological horizons.
Areas of focus:
- optimization algorithms derived from physical dynamics, analyzing its behavior and advantages theoretically and in numerical experiments
- UV complete mechanisms and systematics of cosmic inflation, including string-theoretic versions of large-field inflation (with gravity wave CMB signatures) and novel mechanisms involving inflaton interactions (with non-Gaussian signatures in the CMB)
-Systematic theory and analysis of primordial Non-Gaussianity, taking into account strongly non-linear effects in quantum field theory encoded in multi-point correlation functions
-Long-range interactions in string theory and implications for black hole physics
- Concrete holographic models of de Sitter expansion in string theory, aimed at upgrading the AdS/CFT correspondence to cosmology
- Mechanisms for non-Fermi liquid transport and $2k_F$ singularities from strongly coupled finite density quantum field theory
- Mechanisms by which the extra degrees of freedom in string theory induce transitions and duality symmetries between spaces of different topology and dimensionality -
Jon Simon
Associate Professor of Physics and Applied Physics
Current Research and Scholarly InterestsJon's group focuses on exploring synthetic quantum matter using the unique tools available through quantum and classical optics. We typically think of photons as non-interacting, wave-like particles. By harnessing recent innovations in Rydberg-cavity- and circuit- quantum electrodynamics, the Simonlab is able to make photons interact strongly with one another, mimicking collisions between charged electrons. By confining these photons in ultra-low-loss metamaterial structures, the teams "teach" the photons to behave as though they have mass, are in traps, and are experiencing magnetic fields, all by using the structures to tailor the optical dispersion. In total, this provides a unique platform to explore everything from Weyl-semi-metals, to fractional quantum hall puddles, to Mott insulators and quantum dots, all made of light.
The new tools developed in this endeavor, from twisted fabry-perot resonators, to Rydberg atom ensembles, Floquet-modulated atoms, and coupled cavity optical mode converters, have broad applications in information processing and communication. Indeed, we are now commissioning a new experiment aimed at interconverting optical and mm-wave photons using Rydberg atoms inside of crossed optical and superconducting millimeter resonators as the transducer. -
Todd Smith
Professor (Research) of Physics, Emeritus
BioTodd received his PhD from Rice University. He acted as an assistant professor of physics and electrical engineering, senior research physicist, and professor of physics. Research interests include experimental accelerator physics, laser physics, and superconductivity. His specialty is free electron lasers.
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Leonard Susskind
Felix Bloch Professor of Physics
BioLeonard Susskind is the Felix Bloch professor of Theoretical physics at Stanford University. His research interests include string theory, quantum field theory, quantum statistical mechanics and quantum cosmology. He is a member of the National Academy of Sciences of the USA, and the American Academy of Arts and Sciences, an associate member of the faculty of Canada's Perimeter Institute for Theoretical Physics, and a distinguished professor of the Korea Institute for Advanced Study.
Susskind is widely regarded as one of the fathers of string theory, having, with Yoichiro Nambu and Holger Bech Nielsen, independently introduced the idea that particles could in fact be states of excitation of a relativistic string. He was the first to introduce the idea of the string theory landscape in 2003. -
Mehrnoosh Tahani
Postdoctoral Scholar, Physics
BioMehrnoosh Tahani currently holds a Banting fellowship (sponsored by the government of Canada) hosted at Stanford University and a KIPAC fellowship. She was a research associate (Covington fellow) with the National Research Council Canada at the Dominion Radio Astrophysical Observatory from Sep 2019 to Sep 2022. She received her PhD in 2019 from the University of Calgary.
Her research interests include magnetic fields, molecular clouds, star formation, Faraday rotation, dust polarization, interstellar medium, radio astronomy, magnetohydrodynamic simulations, the 3D shape of magnetic fields of star-forming clouds, and novel techniques for probing interstellar magnetic fields. She is involved in international collaborations such as BISTRO, CCAT-prime, JCMT-transients, and POSSUM.
Mehrnoosh has held teaching positions as a sessional instructor, guest lecturer, and graduate teaching assistant, and has received teaching awards. Her current service roles include co-organizing the Open Cultural Astronomy Forum seminars (https://openculturalastronomyforum.github.io/).
Publication list: https://ui.adsabs.harvard.edu/public-libraries/3whtBFLQRRW_e_qRFf9Z-g -
Lauren Tompkins
Associate Professor of Physics
Current Research and Scholarly InterestsProfessor Tompkins’s research focuses on understanding the relationships which govern matter’s most fundamental constituents. As a member of the ATLAS experiment at the Large Hadron Collider (LHC), she utilizes the world’s highest energy person-made particle collisions in order to understand the mechanism that gives particles mass, whether or not our current model of elementary particle interactions is a complete description of nature, and if dark matter can be produced and studied in colliders.
In order to search for the exceedingly rare interactions which may provide insight to these questions, the LHC will produce a blistering rate of 50 to 80 proton-proton collisions every 25 nanoseconds in 2015 and beyond. Professor Tompkins works on the design and implementation of custom electronics which will improve the ATLAS experiment’s ability to pick out the collisions which produce the Higgs bosons, dark matter particles and other rare events out of the deluge of ordinary interactions. Her group focuses on particles called heavy flavor fermions, the most massive particles not responsible for mediating interactions. Because they are so heavy, they may have a special connection to the origin of mass or physics beyond our current models of particle interactions.
She is additionally a member of the Light Dark Matter Experiment (LDMX), a proposed experiment to produce and detect dark matter in the laboratory utilizing an accelerated beam of electrons. -
John Turneaure
Professor (Research) of Physics, Emeritus
BioJohn received his PhD in physics from Stanford University. He later became a research associate in W.W. Hansen Experimental Physics Laboratory. Following, he acted as an assistant professor of physics, senior research associate, and professor. Research interests include experimental and observational astrophysics and cosmology.
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Robert Wagoner
Professor of Physics, Emeritus
Current Research and Scholarly InterestsProbes (accretion disks, ...) of black holes, sources and detectors of gravitational radiation, theories of gravitation, anthropic cosmological principle.
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Carl Wieman
Cheriton Family Professor and Professor of Physics and of Education, Emeritus
Current Research and Scholarly InterestsThe Wieman group’s research generally focuses on the nature of expertise in science and engineering, particularly physics, and how that expertise is best learned, measured, and taught. This involves a range of approaches, including individual cognitive interviews, laboratory experiments, and classroom interventions with controls for comparisons. We are also looking at how different classroom practices impact the attitudes and learning of different demographic groups.
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Yecun Wu
Postdoctoral Scholar, Physics
BioDr. Yecun Wu is a postdoctoral scholar in the physics department at Stanford University, working with Prof. Steven Chu. His research interests encompass a range of interdisciplinary fields, including quantum sensing, quantum materials, energy storage, and sustainability. Dr. Wu's current research aims to tackle the pressing issues and challenges in the energy field by utilizing quantum technology. He received his Ph.D. in Electrical Engineering from Stanford University, where he worked with Prof. Yi Cui and collaborating closely with Prof. Harold Y. Hwang. During his doctoral studies, he developed innovative methods to control the properties of two-dimensional materials using guest species, which opened new avenues for their use in quantum and energy applications.
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Lin Xin
Postdoctoral Scholar, Physics
BioLin Xin is a Postdoctoral Scholar in the Physics Department at Stanford University. He received his Ph.D. from the Georgia Institute of Technology, following undergraduate studies at Shanghai Jiaotong University. His current research centers on advancing optical control of interactions among laser-cooled atoms, with an eye towards applications in quantum simulation, metrology, and computation. He has developed protocols in quantum optimal control for entanglement-enhanced eigenstates in spinor Bose-Einstein condensates.
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Mason Yearian
Professor of Physics, Emeritus
BioMason received his PhD in physics at Stanford University. Later, he served as an assistant professor, associate professor, and professor at Stanford. Past research includes developing detectors for X-ray and gamma ray astronomy, and work on the GRO/EGRET experiments. Mason also developed a computer-based curriculum for teaching introductory physics courses in high schools and universities.
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Zhefu Yu
Postdoctoral Scholar, Physics
Current Research and Scholarly InterestsMy research aims to understand how supermassive black holes (SMBHs) grow over cosmic time, one of the key questions in astrophysics.
I have done substantial work in accurately measuring the mass of SMBHs through reverberation mapping (RM). In particular, I derived a new relationship between the radius of the Mg II broad line region and the continuum luminosity of the active galactic nuclei (AGN) based on the OzDES RM project, which is critical for SMBH mass measurements and demographic studies in cosmic noon – the peak of AGN activity. I have also done extensive work in understanding the accretion physics in both AGN and quiescent SMBHs.
Now my work focuses on better understanding the accretion onto SMBHs, the major path of SMBH growth. I collaborate closely with the XOC group and the Rubin LSST team in KIPAC. My research probes the inner most region of the AGN accretion disk through joint analysis of the X-ray spectral and timing data. I will also probe the accretion disk through time domain analysis of the LSST data in the near future. -
Richard Zare
Marguerite Blake Wilbur Professor of Natural Science and Professor, by courtesy, of Physics
Current Research and Scholarly InterestsMy research group is exploring a variety of topics that range from the basic understanding of chemical reaction dynamics to the nature of the chemical contents of single cells.
Under thermal conditions nature seems to hide the details of how elementary reactions occur through a series of averages over reagent velocity, internal energy, impact parameter, and orientation. To discover the effects of these variables on reactivity, it is necessary to carry out studies of chemical reactions far from equilibrium in which the states of the reactants are more sharply restricted and can be varied in a controlled manner. My research group is attempting to meet this tough experimental challenge through a number of laser techniques that prepare reactants in specific quantum states and probe the quantum state distributions of the resulting products. It is our belief that such state-to-state information gives the deepest insight into the forces that operate in the breaking of old bonds and the making of new ones.
Space does not permit a full description of these projects, and I earnestly invite correspondence. The following examples are representative:
The simplest of all neutral bimolecular reactions is the exchange reaction H H2 -> H2 H. We are studying this system and various isotopic cousins using a tunable UV laser pulse to photodissociate HBr (DBr) and hence create fast H (D) atoms of known translational energy in the presence of H2 and/or D2 and using a laser multiphoton ionization time-of-flight mass spectrometer to detect the nascent molecular products in a quantum-state-specific manner by means of an imaging technique. It is expected that these product state distributions will provide a key test of the adequacy of various advanced theoretical schemes for modeling this reaction.
Analytical efforts involve the use of capillary zone electrophoresis, two-step laser desorption laser multiphoton ionization mass spectrometry, cavity ring-down spectroscopy, and Hadamard transform time-of-flight mass spectrometry. We believe these methods can revolutionize trace analysis, particularly of biomolecules in cells. -
Sha Zhang
Rsch Admstr 2, Physics
Current Role at StanfordAdministrative associate
