Seminars And Colloquia Next Week

ics Atomic
Monday, February 26, 2018
3:30 PM
Physics Building, Room 204
Erling Riis [Host: Cass Sackett]
University of Strathclyde
"Clocks and interferometers with cold atoms"
ABSTRACT:

The use of cold atoms has led to a substantial increase in the accuracy achievable in many atomic physics measurements. This has most notably been demonstrated in the atomic clock relying on the interference of internal states of weakly interacting atoms in free fall. However, it has also led to an additional layer of experimental complexity which, combined with the physical size of state-of-the-art setups, impose significant limitations on wider practical applications. Progress will be reported on the development of a compact atomic clock based on cold atoms. 

Unprecedented precision has also been demonstrated in atom interferometers relying on the  detection of differential phase shifts between atomic wavefunctions of e.g. different motional states. Sensitivity to external interactions results in a shift of the atomic phase relative to a lab-frame reference, typically the spatial phase of an optical standing wave. This is a limitation to practical measurements as it requires long temporal stability and has motivated the investigation of an atom interferomenter inherently insensitive to the phase noise of the readout system. This relies on an atomic homodyne detection allowing the entire interferometric signal to be read out in a single shot.

ics Nuclear
Tuesday, February 27, 2018
3:30 PM
Physics Building, Room 204

"Available"
ics High Energy
Wednesday, February 28, 2018
3:30 PM
Physics Building, Room 204

"Available"
ics Condensed Matter
Thursday, March 1, 2018
11:00 AM
Physics Building, Room 313
Aaron Wegner [Host: Despina Louca]
UVA- Department of Physics
"Local structure and the Jahn-Teller effect in TiSe2-xTex charge density waves"
ABSTRACT:

Transition metal dichalcogenide (TMDC) materials exhibit a wide variety of interesting physical phenomena. This diverse family of materials forms a quasi-two dimensional layered hexagonal structure of X-M-X sandwiches (M= Ti, Mo, Hf, W, etc.., X= S, Se, Te) that, depending on composition, may be semiconducting, metallic, or superconducting and many undergo charge density wave transitions. As the materials are layered and can be exfoliated, interest in the TMDCs has increased due to the search for graphene-like materials and the importance of thin film applications. One particularly interesting material is TiSe2, which forms a prototypical commensurate CDW that occurs in the vicinity of superconductivity. The origin of this CDW phase is controversial and has alternatively been attributed to exciton condensation or several possible Jahn-Teller type mechanisms. I will discuss how neutron scattering and local structure refinements give insight into the effect of the lattice on CDW formation in TiSe2 and the doping series in which Te is substituted for Se.

ics Special Colloquium


Thursday, March 1, 2018
3:30 PM
Physics Building, Room 204
Note special date.
Dmytro Pesin [Host: Israel Klich ]
University of Utah
"TBA"
ics Colloquium
Friday, March 2, 2018
3:30 PM
Physics Building, Room 204
Peter Schauss [Host: Bob Jones]
Princeton University
"Quantum gas microscopy of many-body dynamics in Fermi-Hubbard and Ising systems"
ABSTRACT:

The ability to probe and manipulate cold atoms in optical lattices at the atomic level using quantum gas microscopes enables quantitative studies of quantum many-body dynamics. While there are many well-developed theoretical tools to study many-body quantum systems in equilibrium, gaining insight into dynamics is challenging with available techniques. Approximate methods need to be benchmarked, creating an urgent need for measurements in experimental model  systems. In this talk, I will discuss two such measurements. First, I will present a study that probes the relaxation of density modulations in the doped Fermi-Hubbard model. This leads to a hydrodynamic description that allows us to determine the conductivity. We observe bad metallic behavior that we compare to predictions from finite-temperature Lanczos calculations and dynamical mean field theory. Second, I introduce a new platform to study the 2D quantum Ising model. Via optical coupling of atoms in an optical lattice to a low-lying Rydberg state, we observe quench dynamics in the resulting Ising model and prepare states with antiferromagnetic correlations.

To add a speaker, send an email to phys-speakers@Virginia.EDU. Please include the seminar type (e.g. Seminars and Colloquia), date, name of the speaker, title of talk, and an abstract (if available).