Theoretical study of atomic physics : cavity QED & Sisyphus cooling

T. Zaugg, Georg Lenz, Pierre Meystre

D. Steck

Hyunchul Nha, Wonho Jhe

We study the cavity QED effects (modified decay rates and energy level shift) of an atom inside a cylindrical hollow fiber and outside a solid fiber using linear-response formalism. Next, we suggest the Sisyphus cooling process occurring inside the hollow fiber with blue-detuned evanescent wave and as a preliminary example, we show a Monte-Carlo simulation of the atoms in the conical hollow system. We also propose that the similar cooling process is expected in the dark hollow beam (doughnut beam) obtained from the hollow fiber of step index, which is more desirable than the case when atoms are inside the fiber since there is no attracting Van der Waals force.

S. Haroche, J. M. Raimond

Lei Tan, Li-Wei Liu, Yu-Qing Zhang

A theoretical study is carried out for the cavity cooling of a $Λ$-type three level atom in a high-finesse optical cavity with a weakly driven field. Analytical expressions for the friction, diffusion coefficients and the equilibrium temperatures are obtained by using the Heisenberg equations, then they are calculated numerically and shown graphically as a function of controlling parameters. For a suitable choice of these parameters, the dynamics of the cavity field interaction with the $Λ$-type three-level atom introduces a sisyphus cooling mechanism yielding lower temperatures below the Doppler limit and allowing larger cooling rate, avoiding the problems induced by spontaneous emission.

A. David. Boozer

In order to study quantum effects such as state superposition and entanglement, one would like to construct simple systems for which the damping rates are slow relative to the rate of coherent evolution. One such system is strong-coupling cavity quantum electrodynamics (QED), in which a single atom is coupled to a single mode of a high finesse optical cavity. In recent years, optical trapping techniques have been applied to the cavity QED system, allowing an individual atom to remain coupled to the cavity for long periods of time. For the purpose of future cavity QED experiments, one would like to gain as much control over the trapped atom as possible; in particular, one would like to cool the center of mass motion of the atom, to measure the magnetic field at the location of the atom, and to be able to prepare the atom in a given internal state. In the first part of this thesis, I present a scheme for driving Raman transitions inside the cavity that can be used to achieve these goals. After giving a detailed theoretical treatment of the Raman scheme, I describe how it can be implemented in the lab and discuss some preliminary experimental results. In the second part of this thesis, I present a number of simple field theory models. These models were developed in an attempt to understand some of the central ideas of theoretical physics by looking at how the ideas work in a highly simplified context. The hope is that by reducing the mathematical complexity of an actual theory, the underlying physical concepts can be more easily understood.