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arXiv · 1011.5639

Excitation Spectra of Bosons in Optical Lattices from Schwinger-Keldysh Calculation

T. D. Grass·F. E. A. dos Santos·A. Pelster
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Abstract

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 transition it turns out that particle/hole dispersions in the Mott phase map continuously onto corresponding amplitude/phase excitations in the superfluid phase, which have been detected recently by Bragg spectroscopy measurements.

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T. D. Grass, F. E. A. dos Santos, A. Pelster. 2010-11-25. Excitation Spectra of Bosons in Optical Lattices from Schwinger-Keldysh Calculation. https://doi.org/10.1103/physreva.84.013613

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