Pseudogap phenomena in a two-dimensional ultracold Fermi gas near the Berezinskii-Kosterlitz-Thouless transition

M. Matsumoto, Yoji Ohashi

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4 Citations (Scopus)

Abstract

We investigate single-particle excitations and strong-coupling effects in a twodimensional Fermi gas. Including pairing fluctuations within a Gaussian fluctuation theory, we calculate the density of states ρ(ω) near the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature TBKT. Near TBKT, we show that superfluid fluctuations induce a pseudogap in ρ(ω). The pseudogap structure is very similar to the BCS superfluid density of states, although the superfluid order parameter is absent in the present two-dimensional case. Since a twodimensional 40K Fermi gas has recently been realized, our results would contribute to the understanding of single-particle properties near the BKT instability.

Original languageEnglish
Article number012012
JournalJournal of Physics: Conference Series
Volume568
DOIs
Publication statusPublished - 2014

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fluctuation theory
gases
transition temperature
excitation

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

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abstract = "We investigate single-particle excitations and strong-coupling effects in a twodimensional Fermi gas. Including pairing fluctuations within a Gaussian fluctuation theory, we calculate the density of states ρ(ω) near the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature TBKT. Near TBKT, we show that superfluid fluctuations induce a pseudogap in ρ(ω). The pseudogap structure is very similar to the BCS superfluid density of states, although the superfluid order parameter is absent in the present two-dimensional case. Since a twodimensional 40K Fermi gas has recently been realized, our results would contribute to the understanding of single-particle properties near the BKT instability.",
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AB - We investigate single-particle excitations and strong-coupling effects in a twodimensional Fermi gas. Including pairing fluctuations within a Gaussian fluctuation theory, we calculate the density of states ρ(ω) near the Berezinskii-Kosterlitz-Thouless (BKT) transition temperature TBKT. Near TBKT, we show that superfluid fluctuations induce a pseudogap in ρ(ω). The pseudogap structure is very similar to the BCS superfluid density of states, although the superfluid order parameter is absent in the present two-dimensional case. Since a twodimensional 40K Fermi gas has recently been realized, our results would contribute to the understanding of single-particle properties near the BKT instability.

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