Atomic Physics Seminars This Term

ics Atomic
Monday, August 28, 2017
3:30 PM
Physics Building, Room 204

"Available"
ics Atomic
Monday, September 11, 2017
3:30 PM
Physics Building, Room 204
RESERVED
ics Atomic
Monday, September 18, 2017
3:30 PM
Physics Building, Room 204

"Available"
ics Atomic
Monday, September 25, 2017
3:30 PM
Physics Building, Room 204
Zubin Jacob [Host: Olivier Pfister]
Purdue University
"Fock state responsivity of single photon detectors"
ABSTRACT:

Highly efficient single photon detectors are ubiquitous in quantum optics and atomic physics. However, many of the theories of single photon detection still arise from the Glauber theory of photodetection which was primarily developed for inefficient detectors (weak light-matter coupling). The first goal of the talk is to contrast the photon counting mechanism in photomultiplier tubes (PMTs), single photon avalanche diodes (SPADs), single electron transistor based photodetectors (SET-PDs) and superconducting nanowire single photon detectors (SNSPDs). This can help develop a general model for single photon detection beyond Glauber's theory. 

Secondly, we will present experimental results on time-correlated single photon counting experiments that demonstrate long range dipole-dipole interactions between quantum emitters mediated by metamaterials.   We will discuss a fundamental limit to the efficiency of energy transfer between quantum emitters and discuss routes to achieve this limit through induced coherence. Our approach to engineering dipole-dipole interactions can motivate experiments from atomic systems (eg: Rydberg blockade) to biochemistry (Forster/Dexter resonance energy transfer).

ics Atomic
Monday, October 9, 2017
3:30 PM
Physics Building, Room 204
RESERVED
ics Atomic
Monday, October 16, 2017
3:30 PM
Physics Building, Room 204
Duncan Tate [Host: Tom Gallagher]
Colby College
"What is the temperature of an ultra-cold Rydberg plasma?"
ABSTRACT:

In this talk, I'll report on a systematic experimental and numerical study of the electron temperature in ultra-cold plasmas which evolve from samples of cold Rydberg atoms. Specifically, we have measured the asymptotic expansion velocities of ultra-cold plasmas (UNPs) which evolve from cold, dense, samples of Rydberg rubidium atoms using ion time-of-flight spectroscopy. From this, we have obtained values for the initial plasma electron temperature, as a function of the original Rydberg atom density and binding energy. We have also simulated numerically the interaction of UNPs with a large reservoir of Rydberg atoms to obtain data to compare with our experimental results. We find that, for n > 40, the electron temperature in the Rydberg plasma is insensitive of the initial ionization mechanism which seeds the plasma. Instead, it is determined principally by the plasma environment when the UNP decouples from the Rydberg atoms at the end of the avalanche regime, and this occurs when the plasma electrons are too cold to ionize the remaining Rydberg population. On the other hand, plasmas from Rydberg samples with n < 40 evolve in a different manner. There is very little additional ionization after the plasma reaches threshold as the electrons in the plasma have insufficient energy to ionize the parent atoms. Consequently, the only significant interaction between the plasma and the parent atoms causes the Rydberg atoms to be de-excited, and the electron temperature equilibrates at a fraction of the initial Rydberg atom binding energy.

ics Atomic
Monday, October 23, 2017
3:30 PM
Physics Building, Room 204

"Available"
ics Atomic
Monday, October 30, 2017
3:30 PM
Physics Building, Room 204
Reserved for Special Nuclear Seminar
ics Atomic
Monday, November 6, 2017
3:30 PM
Physics Building, Room 204
RESERVED
ics Atomic
Monday, November 13, 2017
3:30 PM
Physics Building, Room 204

"Available"
ics Atomic
Monday, November 20, 2017
3:30 PM
Physics Building, Room 204

"Available"
ics Atomic
Monday, November 27, 2017
3:30 PM
Physics Building, Room 204

"Available"
ics Atomic
Monday, December 4, 2017
3:30 PM
Physics Building, Room 204

"Available"

To add a speaker, send an email to tfg@Virginia.EDU Include the seminar type (e.g. Atomic Physics Seminars), date, name of the speaker, title of talk, and an abstract (if available). [Please send a copy of the email to phys-speakers@Virginia.EDU.]