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 $\zeta$ 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 $\zeta$ 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 $\zeta$. Alternating both stages of the cooling process is shown to transfer the atomic gas to a final temperature which vanishes in the infinitely-many particle limit.

Keywords:

• Cavity QED
• collective effects
• laser cooling

Acknowledgements

AB would like to dedicate this paper to her dear and very highly-regarded colleague, Danny Segal, who she met and interacted with during her time at Imperial College London. We also acknowledge inspiring discussions with P. Grangier and thank him for his constructive feedback on the manuscript. Statement of compliance with EPSRC policy framework on research data: This publication is theoretical work that does not require supporting research data.

Notes

No potential conflict of interest was reported by the authors.

1 The collective cavity cooling scheme which we propose here also operates in the bad-cavity limit where g, $\kappa$ and $\mathrm{\Gamma }$ are all of similar size [33]. However making the assumption below simplifies the following calculations and helps us to point out its underlying mechanisms more clearly.

Additional information

Funding

This work was supported by the UK Engineering and Physical Sciences Research Council EPSRC [grant ref. EP/H048901/1]; British Council and DST Government of India.