### 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 language | English |
---|---|

Article number | 033617 |

Journal | Physical Review A - Atomic, Molecular, and Optical Physics |

Volume | 73 |

Issue number | 3 |

DOIs | |

Publication status | Published - 2006 |

Externally published | Yes |

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### ASJC Scopus subject areas

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

### Cite this

*Physical Review A - Atomic, Molecular, and Optical Physics*,

*73*(3), [033617]. https://doi.org/10.1103/PhysRevA.73.033617

**Itinerant-localized dual character of a strongly correlated superfluid Bose gas in an optical lattice.** / Ohashi, Yoji; Kitaura, M.; Matsumoto, H.

Research output: Contribution to journal › Article

*Physical Review A - Atomic, Molecular, and Optical Physics*, vol. 73, no. 3, 033617. https://doi.org/10.1103/PhysRevA.73.033617

}

TY - JOUR

T1 - Itinerant-localized dual character of a strongly correlated superfluid Bose gas in an optical lattice

AU - Ohashi, Yoji

AU - Kitaura, M.

AU - Matsumoto, H.

PY - 2006

Y1 - 2006

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=33645086674&partnerID=8YFLogxK

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U2 - 10.1103/PhysRevA.73.033617

DO - 10.1103/PhysRevA.73.033617

M3 - Article

VL - 73

JO - Physical Review A

JF - Physical Review A

SN - 2469-9926

IS - 3

M1 - 033617

ER -