Eur. Phys. J. D 61, 215-220 (2011)
https://doi.org/10.1140/epjd/e2010-10353-2

Optically-driven cooling for collective atomic excitations

¹ Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
² Institute of Theoretical Physics, The Chinese Academy of Sciences, Beijing, 100190, P.R. China

Corresponding authors: ^a liyonghn@gmail.com - ^b zwang@hkucc.hku.hk - ^c suncp@itp.ac.cn

Received: 14 June 2010
Revised: 23 August 2010
Published online: 5 November 2010

Abstract

We explore how to cool collective atomic excitations in an optically-driven three-level atomic ensemble, which may be described by a model of two coupled harmonic oscillators (HOs) with a time-dependent coupling. Moreover, the model of two coupled HOs is further generalized to address the resolved sideband cooling issues, where the lower-frequency HO can be cooled whenever the cooling process dominates over the heating one during the sideband transitions. Unusually, due to the absence of the heating process, the optimal result for cooling collective excitations in an atomic ensemble could break the standard resolved sideband cooling limit for general models of two coupled HOs.