Spin correlation and superfluidity of trapped fermi atoms on an optical lattice

Masahiko Machida, Susumu Yamada, Yoji Ohashi, Hideki Matsumoto

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We investigate a possibility of superfluidity in a trapped gas of Fermi atoms with repulsive interaction U in the presence of an optical lattice. Applying the exact diagonalization method to a one-dimensional fermion-Hubbard model including the trap potential, we find that, when U exceeds a critical value, the binding energy of two Fermi atoms becomes negative indicating that an attractive interaction effectively works. In this case, a "Mott core" appears in the trap center, where each site is occupied by one atom, and a large Cooper-pair amplitude develops between atoms in the left and right hand sides of this core. In order to clarify the origin of the attractive force, we compute a pseudo spin correlation between neighboring sites given by 〈SiSi+1〉. As a result, we find that a creation of a singlet pair between both sides of the Mott core is strongly coupled with a pseudo-spin singlet re-formation leading to an energy gain process.

Original languageEnglish
Title of host publicationLOW TEMPERATURE PHYSICS
Subtitle of host publication24th International Conference on Low Temperature Physics - LT24
Pages61-62
Number of pages2
DOIs
Publication statusPublished - 2006 Dec 1
EventLOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24 - Orlando, FL, United States
Duration: 2006 Aug 102006 Oct 17

Publication series

NameAIP Conference Proceedings
Volume850
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherLOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24
CountryUnited States
CityOrlando, FL
Period06/8/1006/10/17

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Keywords

  • Atomic fermi gas
  • Cooper pair
  • Exact diagonalization
  • Hubbard model
  • Mott insulator
  • Optical lattice

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Machida, M., Yamada, S., Ohashi, Y., & Matsumoto, H. (2006). Spin correlation and superfluidity of trapped fermi atoms on an optical lattice. In LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24 (pp. 61-62). (AIP Conference Proceedings; Vol. 850). https://doi.org/10.1063/1.2354607