Itinerant-localized dual character of a strongly correlated superfluid Bose gas in an optical lattice

Yoji Ohashi, M. Kitaura, H. Matsumoto

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Abstract

We investigate a strongly correlated Bose gas in an optical lattice. Extending the standard-basis operator method developed by Haley and Erdös to a boson Hubbard model, we calculate excitation spectra in the superfluid phase, as well as in the Mott insulating phase, at T=0. In the Mott phase, the excitation spectrum has a finite energy gap, reflecting the localized character of atoms. In the superfluid phase, the excitation spectrum is shown to have an itinerant-localized dual structure, where the gapless Bogoliubov mode (which describes the itinerant character of superfluid atoms) and a band with a finite energy gap coexist. We also show that the rf-tunneling current measurement would give useful information about the duality of a strongly correlated superfluid Bose gas near the superfluid-insulator transition.

Original languageEnglish
Article number033617
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume73
Issue number3
DOIs
Publication statusPublished - 2006
Externally publishedYes

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ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physics and Astronomy(all)

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