Adiabatic atomic cooling in cavity QED

Constantinos Lazarou, B. M. Garraway

D. Steck

T. Zaugg, Martin Wilkens, Pierre Meystre +1 more

나현철

Thomas Zaugg, Georg Lenz, Pierre Meystre

We discuss an adiabatic cooling scheme particularly adapted to cavity QED situations, and in particular to atoms interacting with microwave cavities of exceedingly high quality factors, where it is desirable to avoid the normal damping mechanism, spontaneous emission.

T. Zaugg

Part I. We analyze how a decaying cavity field can lead to significant atomic cooling. This cooling can be intuitively understood by invoking the adiabatic theorem to characterize the dynamics of an atom dressed by a classical field. We find numerically that cooling can proceed well into the quantum regime where there are only a few photons left in the cavity, and where the adiabatic theorem ceases to be applicable. A physical interpretation of this final cooling stage is given. Part II. We evaluate a nonlinear atomic homodyne detection scheme for measuring the Wigner characteristic function of a microwave cavity field. We find numerically that the semiclassical approximation, on which this scheme is based, does not give results consistent with a full quantum calculation. We analyze the back-action of the measurements on steady-state 'macroscopic superpositions' that can be generated in high-Q microwave cavities. We show that the measurements required for a full characterization of the state destroys the macroscopic superposition such that it cannot be reconstructed by using the scheme that was used to generate it in the first place.