Laser spectroscopic probing of coexisting superfluid and insulating states of an atomic Bose-Hubbard system

Shinya Kato, Kensuke Inaba, Seiji Sugawa, Kosuke Shibata, Ryuta Yamamoto, Makoto Yamashita, Yoshiro Takahashi

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

A system of ultracold atoms in an optical lattice has been regarded as an ideal quantum simulator for a Hubbard model with extremely high controllability of the system parameters. While making use of the controllability, a comprehensive measurement across the weakly to strongly interacting regimes in the Hubbard model to discuss the quantum many-body state is still limited. Here we observe a great change in the excitation energy spectra across the two regimes in an atomic Bose-Hubbard system by using a spectroscopic technique, which can resolve the site occupancy in the lattice. By quantitatively comparing the observed spectra and numerical simulations based on sum rule relations and a binary fluid treatment under a finite temperature Gutzwiller approximation, we show that the spectra reflect the coexistence of a delocalized superfluid state and a localized insulating state across the two regimes.

Original languageEnglish
Article number11341
JournalNature communications
Volume7
DOIs
Publication statusPublished - 2016 Apr 20

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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