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

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.

7 pages,6 figures

References in corpus (12)

• Strong atom-field coupling for Bose-Einstein condensates in an optical cavity on a chip
• Cavity QED with a Bose-Einstein condensate
• Quantum criticality as a resource for quantum estimation
• Dynamical quantum phase transitions in the dissipative Lipkin-Meshkov-Glick model and proposed realization in optical cavity QED
• Mott insulator states of ultracold atoms in optical resonators
• Critical Property of Geometric Phase in the Dicke Model
• Exotic quantum phase transitions in a Bose-Einstein condensate coupled to an optical cavity
• Mean-field dynamics of a Bose Josephson junction in an optical cavity
• Polaritons and Pairing Phenomena in Bose--Hubbard Mixtures
• Excess noise depletion of a Bose-Einstein condensate in an optical cavity
• Universal Critical Behavior in the Dicke Model
• Ultracold atoms in a cavity mediated double-well system