Many-body physics in two-component Bose–Einstein condensates in a cavity: fragmented superradiance and polarization. (15th May 2018)

• Record Type: Journal Article
• Authors: Lode, Axel U J; Diorico, Fritz S; Wu, RuGway; Molignini, Paolo; Papariello, Luca; Lin, Rui; Lévêque, Camille; Exl, Lukas; Tsatsos, Marios C; Chitra, R; Mauser, Norbert J
• Is Part Of: New journal of physics. Volume 20:Number 5(2018:May)
• Publication Date: 2018-05-15
• Subjects: many-body systems -- time-dependent Schrödinger equation -- Bose–Einstein condensates -- light–matter interaction -- multi-component systems -- MCTDHB; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aabc3a
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: We consider laser-pumped one-dimensional two-component bosons in a parabolic trap embedded in a high-finesse optical cavity. Above a threshold pump power, the photons that populate the cavity modify the effective atom trap and mediate a coupling between the two components of the Bose–Einstein condensate. We calculate the ground state of the laser-pumped system and find different stages of self-organization depending on the power of the laser. The modified potential and the laser-mediated coupling between the atomic components give rise to rich many-body physics: an increase of the pump power triggers a self-organization of the atoms while an even larger pump power causes correlations between the self-organized atoms—the BEC becomes fragmented and the reduced density matrix acquires multiple macroscopic eigenvalues. In this fragmented superradiant state, the atoms can no longer be described as two-level systems and the mapping of the system to the Dicke model breaks down.