School of Humanities and Sciences
Showing 1,601-1,700 of 2,083 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. -
Michael Simon
Professor of Biology
Current Research and Scholarly InterestsPlanar cell polarity, cell shape and mobility, and control of cell fate
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Robert Simoni
Professor, Biology
Current Research and Scholarly InterestsCholesterol in biological membranes; genetic mechanisms & cholesterol production
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Jan Skotheim
Professor of Biology and, by courtesy, of Chemical and Systems Biology
Current Research and Scholarly InterestsMy overarching goal is to understand how cell growth triggers cell division. Linking growth to division is important because it allows cells to maintain specific size range to best perform their physiological functions. For example, red blood cells must be small enough to flow through small capillaries, whereas macrophages must be large enough to engulf pathogens. In addition to being important for normal cell and tissue physiology, the link between growth and division is misregulated in cancer.
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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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Edward I. Solomon
Monroe E. Spaght Professor of Chemistry and Professor of Photon Science
On Leave from 04/01/2024 To 06/30/2024Current Research and Scholarly InterestsProf. Solomon's work spans physical-inorganic, bioinorganic, and theoretical-inorganic chemistry, focusing on spectroscopic elucidation of the electronic structure of transition metal complexes and its contribution to reactivity. He has advanced our understanding of metal sites involved in electron transfer, copper sites involved in O2 binding, activation and reduction to water, structure/function correlations over non-heme iron enzymes, and correlation of biological to heterogeneous catalysis.
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Richard Sommer
Lecturer
BioRick Sommer received both his bachelors and PhD degrees in Mathematics from UC Berkeley, where he began his research in mathematical logic. Rick held a research position at MSRI in 1989 - 1990, and became a Gabor Szego Assistant Professor in the Department of Mathematics at Stanford in 1990. In 1995, Rick co-founded the Stanford University Mathematics Camp, for which he served as Director for over 25 years, and continues in a role as Special Advisor and Instructor. Also in the mid-90s, Rick took on a leadership role in developing online courses and residential summer programs for Stanford's Education Program for Gifted Youth (EPGY). In 2012, EPGY transformed into Stanford Pre-Collegiate Studies (SPCS), providing a home to the Stanford Online High School as well as over a dozen summer and year-around pre-collegiate programs, many of which Rick played a role in designing, developing and leading. Rick served as Executive Director of SPCS from 2015-2020. Rick occasionally teaches Logic in the Philosophy Department (Phil 151 and 152) and Set Theory in the Math Department (Math 161). Rick has a strong interest in mathematics education, and more generally in educational programs designed to inspire and develop the curiosity of young people. Rick is Co-Founder and Board Member of AI4ALL, working to increase diversity in the leadership of AI, and he is Treasurer and Board Member of the Gathering for Gardner Foundation, stimulating curiosity and the playful exchange of ideas in mathematics and related fields, in the spirit of Martin Gardner.
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Daniel Stack
Associate Professor of Chemistry
On Leave from 04/01/2024 To 06/30/2024BioResearch in the Stack group focuses on the mechanism of dioxygen activation and the subsequent oxidative reactivity with primarily copper complexes ligated by imidazoles or histamines. Specifically, the group is interested in substrate hydroxylations and full dioxygen reduction. The remarkable specificity and energy efficiency of metalloenzymes provide the inspiration for the work. Trapping and characterizing immediate species, primarily at low temperatures, provide key mechanistic insights especially through substrate reactivity along with spectroscopic and metrical correlation to DFT calculations. Our objective is to move these efficient enzymatic mechanisms into small synthetic complexes, not only to reproduce biological reactivity, but more importantly to move the oxidative mechanism beyond that possible in the protein matrix.
Daniel Stack was born, raised and attended college in Portland Oregon. He received his B.A. from Reed College in 1982 (Phi Beta Kappa), working with Professor Tom Dunne on weak nickel-pyrazine complexes. In Boston, he pursued his doctoral study in synthetic inorganic chemistry at Harvard University (Ph.D., 1988) with Professor R. H. Holm, investigating site-differentiated synthetic analogues of biological Fe4S4 cubanes. As an NSF Postdoctoral Fellow with Professor K. N. Raymond at the University of California at Berkeley, he worked on synthesizing new, higher iron affinity ligands similar to enterobactin, a bacterial iron sequestering agent. He started his independent career in 1991 at Stanford University primarily working on oxidation catalysis and dioxygen activation, and was promoted to an Associate Professor in 1998. His contributions to undergraduate education have been recognized at the University level on several occasions, including the Dinkelspiel Award for Outstanding Contribution to Undergraduate Education in 2003.
Areas of current focus include:
Copper Dioxygen Chemistry
Our current interests focus on stabilizing species formed in the reaction of dioxygen with Cu(I) complexes formed with biologically relevant imidazole or histamine ligation. Many multi-copper enzymes ligated in this manner are capable of impressive hydroxylation reactions, including oxidative depolymerization of cellulose, methane oxidation, and energy-efficient reduction of dioxygen to water. Oxygenation of such complexes at extreme solution temperatures (-125°C) yield transient Cu(III) containing complexes. As Cu(III) is currently uncharacterized in any biological enzyme, developing connections between the synthetic and biological realms is a major focus.
Surface Immobilization of Catalysts in Mesoporous Materials
In redox active biological metal sites, the ligation environment is coupled tightly to the functional chemistry. Yet, the metal sites are also site-isolated, creating species that may only have a transient existence in a homogeneous solution. Site isolation of synthetic complexes can be achieved synthetically by supporting the metal complex on a solid matrix. Movement of these complexes into silica based materials or onto electroactive carbon electrodes represent a new direction for the group in the development of bio-inspired metal-based catalysts. -
Tim Stearns
Professor of Biology
Current Research and Scholarly InterestsWe use the tools of genetics, microscopy, and biochemistry to understand fundamental questions of cell biology: How are cells organized by the cytoskeleton? How do the centrosome and cilium control cell control cell signaling? How is cell division coordinated with duplication of the centrosome, and what goes wrong in cancer cells defective in this coordination?
