Damping of quasiparticles in a Bose-Einstein condensate coupled to an optical cavity

G. Kónya, G. Szirmai, P. Domokos

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

We present a general theory for calculating the damping rate of elementary density-wave excitations in a Bose-Einstein condensate strongly coupled to a single radiation field mode of an optical cavity. Thereby we give a detailed derivation of the huge resonant enhancement in the Beliaev damping of a density-wave mode, predicted recently by Kónya et al. [Phys. Rev. A 89, 051601(R) (2014)PLRAAN1050-294710.1103/PhysRevA.89.051601]. The given density-wave mode constitutes the polaritonlike soft mode of the self-organization phase transition. The resonant enhancement takes place, in both the normal and the ordered phases, outside the critical region. We show that the large damping rate is accompanied by a significant frequency shift of this polariton mode. Going beyond the Born-Markov approximation and determining the poles of the retarded Green's function of the polariton, we reveal a strong coupling between the polariton and a collective mode in the phonon bath formed by the other density-wave modes.

Original languageEnglish
Article number013623
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume90
Issue number1
DOIs
Publication statusPublished - Jul 25 2014

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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