Latest News and Research
Latest News and Research
Photon-counting calibrationsCalibrating an optical attenuator with few-photon pulses
- November 4, 2015
- Research News
From NIST-PML — Precise measurements of optical power enable activities from fiber-optic communications to laser manufacturing and biomedical imaging — anything requiring a reliable source of light. This situation calls for light-measuring (radiometric) standards that can operate over a wide range of power levels.
Currently, however, different methods for calibrating... Continue Reading
At the edge of a quantum gasJQI physicists observe skipping orbits in the quantum Hall regime
From NIST-PML--JQI scientists have achieved a major milestone in simulating the dynamics of condensed-matter systems – such as the behavior of charged particles in semiconductors and other materials – through manipulation of carefully controlled quantum-mechanical models.
Going beyond their pioneering experiments in 2009 (the creation of “... Continue Reading
Twisting NeutronsOrbital angular momentum of neutron waves can be controlled
- September 23, 2015
- Research News
It’s easy to contemplate the wave nature of light in common experience. White light passing through a prism spreads out into constituent colors; it diffracts from atmospheric moisture into a rainbow; light passing across a sharp edge or a diffraction grating creates an interference pattern. It’s harder to fathom the wave behavior of things usually thought of as particles, such as electrons... Continue Reading
JQI Physicists Show ‘Molecules’ Made of Light May Be Possible
From NIST TechBeat--It’s not lightsaber time, not yet. But a team including theoretical physicists from JQI and NIST has taken another step toward building objects out of photons, and the findings, recently published in Physical Review Letters, hint that weightless particles of light can be joined into a sort of “molecule” with its own peculiar force. Researchers show... Continue Reading
Strange Metallic BehaviorThe first 2-Way, 2-dim, Ultra-high Mobility Si (111) Transistor
- September 2, 2015
- Research News
The two-dimensional physical properties of semiconductor materials depend keenly on a number of factors, such as material purity, surface orientation, flatness, surface reconstruction, charge carrier polarity, and temperature. JQI (*) scientists have optimized a number of these parameters to produce the first ever ultra-high mobility, two-dimensional Si(111) transistor that allows charge... Continue Reading
Experimental quantum physics often resides in the coldest regimes found in the universe, where the lack of large thermal disturbances allows quantum effects to flourish. A key ingredient to these experiments is being able to measure just how cold the system of interest is. Laboratories that produce ultracold gas clouds have a simple and reliable method to do this: take pictures! The... Continue Reading
James R. Williams
James R. Williams is a JQI Fellow and assistant professor of physics, and his chief area of research is experimental condensed matter physics. Specifically, he specializes in understanding why certain one and two-dimensional materials (e.g. topological insulators, graphene) depart from normal conductivity provided by free electrons.
Jimmy, as he likes to be called, almost didn’t go to college. All he wanted to do was work on cars. His mother forced him to apply to one college, so he choose Santa Clara University where he previously attended a basketball camp. He majored in engineering, but his favorite courses involved physics, so he changed direction again. This is how he arrived at his chosen area of research.
Eventually he got a PhD from Harvard University in 2009 on the subject of grapheme, while studying under Charles M. Marcus. He was then a postdoctoral fellow at Stanford before coming to Maryland.
Ryan Barnett, a former JQI postdoctoral fellow at the Condensed Matter Theory Center (CMTC), is now a ‘Lecturer in Condensed Matter Theory’ (UK equivalent of assistant professor) at Imperial College in London. Ryan is a theoretical physicist interested in collective effects in ultracold atomic gases. While at the JQI his research focused on spinor condensates, non-equilibrium dynamics, and synthetic gauge fields. Much of his recent work at CMTC was motivated by ongoing experimental activities at the JQI.
Crystal Senko was a graduate student in Chris Monroe's ion trapping group. While in the group she focused on ultrafast spin manipulation as well as quantum simulation of magnetism. She is now a postdoctoral researcher with Mikhail Lukin at Harvard. Senko is an undergraduate alumni of Duke University, where she worked with Dan Gauthier on magneto-optical trapping using distributed feedback lasers.
Phil Richerme is a postdoc in Chris Monroe's Trapped Ion Quantum Information Group. He studies quantum magnetism using a well-controlled and well-isolated system of atomic ion spins, realizing Feynman's original proposal for a quantum simulator. These experiments probe the ground state and dynamical evolution of interacting spin systems, which are difficult (or impossible) for classical computers to calculate for even a few dozen spins. Phil received his Ph.D. from Harvard in 2012, working with Gerald Gabrielse and the ATRAP collaboration at CERN to trap antihydrogen atoms for sensitive tests of CPT symmetry.
Stephen Powell, a former JQI postdoctoral fellow at CMTC, now works at the Nordic Institute of Theoretical Physics or Nordita in Stockholm, Sweden. His research in the group of Sankar Das Sarma centered around strongly correlated systems with a specific focus on frustrated magnetism and ultracold gases. At Nordita, he will continue this line of research, which is at the meeting point of condensed matter and atomic physics. In talking of his postdoctoral experience he says, “Something I've particularly enjoyed about being at JQI is having close contact with various experimental groups here.”
Hafezi is JQI fellow and works at the interface of condensed matter theory and quantum optics. The focus of his research is on theoretical and experimental investigations of artificial gauge fields and topological order in photonics systems. Such systems can be exploited as robust optical devices insensitive to disorder, which is the subject of his NSF Physics Frontier Center’s seed funding program. Moreover, in the presence of strong optical nonlinearity, such systems are expected to exhibit fractional quantum Hall physics, providing a platform for potentially observing anoynic statistics. He received his Ph.D. from Harvard in 2009 where he worked with Mikhail Lukin and Eugene Demler. There, he studied strongly correlated physics in AMO systems. In particular, he worked on the topological characterization of ultracold atoms in 2D and also non-equilibrium dynamics of strongly interacting photons in 1D.
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