Cooling a quantum gas by losses

Florian Schreck, N. J. van Druten

K. Okada, M. Wada, Takashi Nakamura +3 more

A cryogenic linear ion trap was developed for the minimization of the loss of trapped Be+ ions. Buffer gas cooling as well as laser cooling for light element ions was tested in the cryogenic trap. The lifetime for the He-gas-cooled Be+ ions was longer than 15 min with a liquid-He-cooled trap, although they are known to be difficult to cool with a buffer gas in a conventional trap. A laser-cooled ion crystal was maintained for approximately 30 min without any ion loss.

Zbigniew Idziaszek, Luis Santos, Maciej Lewenstein

We study the sympathetic cooling of a trapped Fermi gas interacting with an ideal Bose gas below the critical temperature of the Bose-Einstein condensation. We derive the quantum master equation, which describes the dynamics of the fermionic component, and postulating the thermal distribution for both gases we calculate analytically the rate at which fermions are cooled by the bosonic atoms. The particle losses constitute an important source of heating of the degenerate Fermi gas. We evaluate the rate of loss-induced heating and derive analytical results for the final temperature of fermions, which is limited in the presence of particle losses.

Jakub Meisner

A.N Lebedev

Zbigniew Idziaszek, Luis Santos, M. Baranov +1 more

We study the collective Raman cooling of a trapped two-component Fermi gas using quantum master equation in the festina lente regime, where the heating due to photon reabsorption can be neglected. The Monte Carlo simulations show that three-dimensional temperatures of the order of ${0.008T}_{F}$ can be achieved. We analyze the heating related to background losses, and show that our laser-cooling scheme can maintain the temperature of the gas without significant additional losses.