Click here for a printable version of this page.
Atomic Physics Seminars
| Special Colloquium/Atomic Seminar
Monday, February 14, 2000
Physics Building, Room 203
Note special time.
Note special room.
[Host: Louis Bloomfield]
"Quantum Noise in Simple Atomic Systems"
Counter-intuitive predictions of quantum mechanics are most
readily explored in the field of optics, where table-top experiments
suffice to make sensitive measurements. A single atom, radiating in free
space, is the simplest and most fundamental quantum optical system. It is
particularly attractive for study of multiple measurements on a quantum
system because, quite unlike the situation for a classical radiator, the
detection of a radiated photon directly affects the probability of a
subsequent emission. Indeed, measurement of fluctuations in the radiated
intensity provided the first experimental evidence for such
counter-intuitive quantum effects as photon antibunching and
sub-Poissonian light. However, quantum fluctuations in the optical phase
of the radiated light remain relatively unexplored. Especially remarkable
is the fact that "squeezing" in single-atom fluorescence, a
phase-sensitive quantum effect first predicted in 1981, has long eluded
direct observation despite receiving considerable attention. The reason is
that measurement of phase-sensitive nonclassical effects in atomic
fluorescence presents severe experimental challenges.
In this talk I will describe how we recently overcame these challenges to
make the first measurements of single-atom squeezing spectra in the
phase-dependent fluorescence of atoms radiating in free space. Our
experimental scheme permits a valid comparison of the observations with
our predictions, thus yielding a new and simple physical picture of
phase-dependent quantum noise in atomic fluorescence. Results of a direct
measurement of the two-time field correlations will also be presented. Our
measurements help elucidate the basic atomic processes underlying
"squeezing". Our observations are especially important because the
measurement accuracy in current state-of-the-art cold atom interferometers
and frequency standards is limited by quantum noise. Controlling the
phase-dependent quantum noise may enable measurement beyond quantum
To add a speaker, send an email to
Please include the seminar type (e.g. Atomic Physics Seminars), date, name of the speaker, title of talk, and an abstract (if available).