Real-Time Ginzburg-Landau Theory for Bosons in Optical Lattices

Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for the Bose-Hubbard model which describes the real-time dynamics of the complex order parameter field. Analyzing the excitations in the vicinity of the quantum phase transitions it turns out that particle/hole dispersions in...

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Bibliographic Details
Published inarXiv.org
Main Authors Grass, T D, F E A dos Santos, Pelster, A
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 22.03.2010
Subjects
Bosons
Dispersions
Excitation
Fluids
Optical lattices
Order parameters
Phase transitions
Physics - Quantum Gases
Real time
Superfluidity
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Summary:Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for the Bose-Hubbard model which describes the real-time dynamics of the complex order parameter field. Analyzing the excitations in the vicinity of the quantum phase transitions it turns out that particle/hole dispersions in the Mott phase map continuously onto corresponding amplitude/phase excitations in the superfluid phase. Furthermore, in the superfluid phase we find a sound mode, which is in accordance with recent Bragg spectroscopy measurements in the Bogoliubov regime, as well as an additional gapped mode, which seems to have been detected via lattice modulation.
ISSN:2331-8422
DOI:10.48550/arxiv.1003.4197