Cavity-mediated collective laser-cooling of a non-interacting atomic gas inside an asymmetric trap to very low temperatures

Abstract

In this paper, we identify a many-particle phonon expectation value ζ with the ability to induce collective dynamics in a non-interacting atomic gas inside an optical cavity. We then propose to utilise this expectation value to enhance the laser cooling of many atoms through a cyclic two-stage process which consists of cooling and displacement stages. During cooling stages, short laser pulses are applied. These use ζ as a resource and decrease the vibrational energy of the atomic gas by a fixed amount. Subsequent displacement stages use the asymmetry of the trapping potential to replenish the many-particle phonon expectation value ζ. Alternating both stages of the cooling process is shown to transfer the atomic gas to a final temperature which vanishes in the infinitelymany particle limit.

A Quantum Heat Exchanger for Nanotechnology

“…In this section, we first have a closer look at a standard laser cooling technique for an individually trapped atomic particle [ 19 , 20 ]. Afterwards, we review cavity-mediated laser cooling of a single atom [ 42 , 43 , 44 , 45 , 46 ] and of an atomic gas [ 26 , 27 , 28 ].…”

“…In the experimental setup in Figure 3 , all transitions which result in the excitation of the atom are naturally strongly detuned and can be neglected. However, the same does not have to apply to indirect couplings which result in the direct conversion of phonons into cavity photons [ 27 , 44 ]. Suppose the cavity detuning and the phonon frequency are approximately the same and the cavity decay rate does not exceed , in analogy to Equations ( 1 ) and ( 2 ).…”

“…Finally, we have a closer look at cavity-mediated collective laser cooling of an atomic gas inside an optical resonator [ 26 , 27 ]. To do so, we replace the single atom in the experimental setup in Figure 3 by a collection of N atoms.…”

“…In this paper, we propose an alternative approach. More concretely, we propose to use heat transfer as well as a variation of laser cooling, namely cavity-mediated collective laser cooling [ 24 , 25 , 26 , 27 , 28 ], to lower the temperature of a small device. As illustrated in Figure 1 , the proposed quantum heat exchanger mainly consist of a liquid which contains a large number of cavitating bubbles filled with noble gas atoms.…”

The role of quantum coherence in dimer and trimer excitation energy transfer

“…There are different processes where quantum coherence has been shown to enhance the outcome in some aspect, i.e., function as a resource. Examples can be found in quantum thermodynamics [14][15][16][17][18] and photocells [19,20]. A mechanism for which the importance of quantum coherence has been widely discussed and studied over the last years is excitation energy transfer (EET) in photosynthetic complexes.…”