Events at Physics |
Events During the Week of December 14th through December 21st, 2014
Monday, December 15th, 2014
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:15 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
http://cmb.physics.wisc.edu/journal/index.html
Please feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Le Zhang (lzhang263@wisc.edu) - Host: Peter Timbie
Tuesday, December 16th, 2014
- R. G. Herb Condensed Matter Seminar
- Atomic Physics Seminar
- Extending the quantum domain with quantum optics
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Christoph Simon, University of Calgary
- Abstract: Quantum optical systems are well suited for pushing the boundaries of quantum physics. Two big goals in this context are the creation of entanglement over long distances and the observation of quantum effects on macroscopic scales. I will describe various theoretical and some experimental work in these directions. In particular I am planning to discuss quantum repeaters with multimode quantum memories, the potential for global entanglement using satellite links and repeaters, work towards the quantum non-demolition detection of photonic qubits in rare-earth doped crystals, ideas on photon-photon gates based on Rydberg states, an experiment creating micro-macro entanglement of light, and a proposal for spin cat states in Bose-Einstein condensates.
- Host: Saffman
- Atomic Physics Seminar
- R. G. Herb Condensed Matter Seminar
- TBD
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Christoph Simon, University of Calgary
- Abstract: TBD
- Host: Saffman
Wednesday, December 17th, 2014
- Atomic Physics Seminar
- Application of mesoscopic atomic ensembles with random number of atoms to quantum information and quantum optics
- Time: 10:00 am
- Place: 5310 Chamberlin hall
- Speaker: Ilya Beterov, Rzhanov Institute of Semiconductor Physics :Novosibirsk State University: Novosibirsk, Russia
- Abstract: Mesoscopic ensembles of ultracold interacting atoms can be implemented by loading the cold atoms into an optical dipole trap. These ensembles are of interest for encoding of quantum information, generation of collective entangled states and observation of cooperative effects in atom-light interactions. Long-range interactions between the atoms in the ensemble lead to the effect of Rydberg blockade when not more than one atom could be excited into a Rydberg state by a narrow-band laser radiation.
The number of atoms in the trap is random and is commonly described by the Poissonian statistics. In the regime of Rydberg blockade an atomic ensemble, which consists of N atoms, can be treated as a two-level system with enhanced coupling to the laser radiation field by a factor of compared to a single atom. A single Rydberg excitation is shared between all atoms in the ensemble. Fluctuations of the frequency of Rabi oscillations between the collective states of the atomic ensembles can result in collapses and revivals of Rabi oscillations, similarly to Jaynes-Cummings model in quantum optics. These fluctuations can also lead to significant errors in quantum information processing. We have proposed to use the adiabatic passage in atomic ensembles for deterministic single-atom excitation and quantum logic gates in ensembles with unknown numbers of atoms. The double adiabatic sequences provide deterministic single-atom Rydberg excitation and remove the accumulation of undesirable dynamic phase. This can be used to implement quantum gates on collectively encoded qubits without precise knowledge of N.
- Host: Saffman
Thursday, December 18th, 2014
- R. G. Herb Condensed Matter Seminar
- Hydrodynamic Coulomb and Hall drag of strongly correlated electron liquids
- Time: 10:00 am - 11:00 am
- Place: Chamberlin 5310
- Speaker: Alex Levchenko, Michigan State University
- Abstract: We develop a theory of drag resistivity in ultraclean double layers with strongly correlated carriers. In the regime where the equilibration length of the electron liquid is shorter than the interlayer spacing the main contribution to the drag arises from hydrodynamic density fluctuations. The latter consist of plasmons driven by fluctuating longitudinal stresses, and diffusive modes caused by temperature fluctuations and thermal expansion of the electron liquid. We express the drag resistivity tensor in terms of the kinetic coefficients of the electron fluid. Our results are nonperturbative in interaction strength and do not assume Fermi-liquid behavior of the electron liquid.
- Host: Vavilov
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- An Effective Field Theory Analysis of the LUX WIMP Search
- Time: 2:30 pm - 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Nicole Larsen, Yale University
- Abstract: The Large Underground Xenon (LUX) experiment is a dark matter direct detection experiment located 4850 feet underground at the Sanford Underground Research Facility in Lead, SD. During Summer 2013, LUX collected 10065 kg-days of WIMP search data. Ultimately LUX reported a minimum cross-section limit for spin-independent WIMP-nucleon elastic scattering of 7.6 e-46 cm2 for 33-GeV WIMPs, making it the most sensitive direct detection experiment to date. Direct detection experiments like LUX typically only present limits on spin-independent (SI) and spin-dependent (SD) WIMP-nucleon interaction cross sections. However, recent theoretical work has emphasized that in the most general effective field theory formulation there are several additional momentum-dependent and velocity-dependent interactions allowed by basic symmetries that can interfere with or modify the standard SI and SD interactions. Moreover, entirely new nuclear responses analogous to angular-momentum-dependent and spin-orbit couplings in standard weak interaction theory can emerge. Here I provide an overview of the LUX detector and last year’s WIMP search run, discuss the current status of the experiment, and highlight recent efforts toward using the LUX 2013 dataset to set limits on these new momentum- and velocity-dependent operators.
- Host: Westerhoff
Friday, December 19th, 2014
- No events scheduled