English

Nonlinear Atom-Photon Interaction Induced Population Inversion and Inverted Quantum Phase Transition of Bose-Einstein Condensate in an Optical Cavity

Quantum Gases 2015-06-19 v1 Quantum Physics

Abstract

In this paper we explore the rich structure of macroscopic many-particle quantum states for Bose- Einstein condensate in an optical cavity with the tunable nonlinear atom-photon interaction [Nature (London) 464, 1301 (2010)]. Population inversion, bistable normal phases and the coexistence of normal{superradiant phases are revealed by adjusting of the experimentally realizable interaction strength and pump-laser frequency. For the negative (effective) cavity-frequency we observe remark- ably an inverted quantum phase transition (QPT) from the superradiant to normal phases with the increase of atom-field coupling, which is just opposite to the QPT in the normal Dicke model. The bistable macroscopic states are derived analytically in terms of the spin-coherent-state variational method by taking into account of both normal and inverted pseudospin states.

Keywords

Cite

@article{arxiv.1405.5612,
  title  = {Nonlinear Atom-Photon Interaction Induced Population Inversion and Inverted Quantum Phase Transition of Bose-Einstein Condensate in an Optical Cavity},
  author = {Xiuqin Zhao and Ni Liu and J-Q Liang},
  journal= {arXiv preprint arXiv:1405.5612},
  year   = {2015}
}

Comments

7 pages,6 figures