π junction and spontaneous current state in a superfluid Fermi gas

Takashi Kashimura, Shunji Tsuchiya, Yoji Ohashi

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We discuss an idea to realize a spontaneous current in a superfluid Fermi gas. When a polarized Fermi superfluid (NN, where Nσ is the number of atoms in the hyperfine state described by pseudospin σ=) is loaded onto a ring-shaped trap with a weak potential barrier, some excess atoms (ΔN=N-N) are localized around the barrier. As shown in our previous paper, this polarized potential barrier works as a π junction in the sense that the superfluid order parameter changes its sign across the barrier. Because of this, the phase of the superfluid order parameter outside the junction is shown to be twisted by π along the ring, which naturally leads to a circulating supercurrent. While the ordinary supercurrent state is obtained as a metastable state, this spontaneous current state is shown to be more stable than the case with no current. Our results indicate that localized excess atoms would be useful for the manipulation of the superfluid order parameter in cold Fermi gases.

Original languageEnglish
Article number013609
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Volume84
Issue number1
DOIs
Publication statusPublished - 2011 Jul 20
Externally publishedYes

Fingerprint

gases
atoms
rings
metastable state
manipulators
traps

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

π junction and spontaneous current state in a superfluid Fermi gas. / Kashimura, Takashi; Tsuchiya, Shunji; Ohashi, Yoji.

In: Physical Review A - Atomic, Molecular, and Optical Physics, Vol. 84, No. 1, 013609, 20.07.2011.

Research output: Contribution to journalArticle

@article{7187b34b7103445c9ee2d937215cb137,
title = "π junction and spontaneous current state in a superfluid Fermi gas",
abstract = "We discuss an idea to realize a spontaneous current in a superfluid Fermi gas. When a polarized Fermi superfluid (NN, where Nσ is the number of atoms in the hyperfine state described by pseudospin σ=) is loaded onto a ring-shaped trap with a weak potential barrier, some excess atoms (ΔN=N-N) are localized around the barrier. As shown in our previous paper, this polarized potential barrier works as a π junction in the sense that the superfluid order parameter changes its sign across the barrier. Because of this, the phase of the superfluid order parameter outside the junction is shown to be twisted by π along the ring, which naturally leads to a circulating supercurrent. While the ordinary supercurrent state is obtained as a metastable state, this spontaneous current state is shown to be more stable than the case with no current. Our results indicate that localized excess atoms would be useful for the manipulation of the superfluid order parameter in cold Fermi gases.",
author = "Takashi Kashimura and Shunji Tsuchiya and Yoji Ohashi",
year = "2011",
month = "7",
day = "20",
doi = "10.1103/PhysRevA.84.013609",
language = "English",
volume = "84",
journal = "Physical Review A",
issn = "2469-9926",
publisher = "American Physical Society",
number = "1",

}

TY - JOUR

T1 - π junction and spontaneous current state in a superfluid Fermi gas

AU - Kashimura, Takashi

AU - Tsuchiya, Shunji

AU - Ohashi, Yoji

PY - 2011/7/20

Y1 - 2011/7/20

N2 - We discuss an idea to realize a spontaneous current in a superfluid Fermi gas. When a polarized Fermi superfluid (NN, where Nσ is the number of atoms in the hyperfine state described by pseudospin σ=) is loaded onto a ring-shaped trap with a weak potential barrier, some excess atoms (ΔN=N-N) are localized around the barrier. As shown in our previous paper, this polarized potential barrier works as a π junction in the sense that the superfluid order parameter changes its sign across the barrier. Because of this, the phase of the superfluid order parameter outside the junction is shown to be twisted by π along the ring, which naturally leads to a circulating supercurrent. While the ordinary supercurrent state is obtained as a metastable state, this spontaneous current state is shown to be more stable than the case with no current. Our results indicate that localized excess atoms would be useful for the manipulation of the superfluid order parameter in cold Fermi gases.

AB - We discuss an idea to realize a spontaneous current in a superfluid Fermi gas. When a polarized Fermi superfluid (NN, where Nσ is the number of atoms in the hyperfine state described by pseudospin σ=) is loaded onto a ring-shaped trap with a weak potential barrier, some excess atoms (ΔN=N-N) are localized around the barrier. As shown in our previous paper, this polarized potential barrier works as a π junction in the sense that the superfluid order parameter changes its sign across the barrier. Because of this, the phase of the superfluid order parameter outside the junction is shown to be twisted by π along the ring, which naturally leads to a circulating supercurrent. While the ordinary supercurrent state is obtained as a metastable state, this spontaneous current state is shown to be more stable than the case with no current. Our results indicate that localized excess atoms would be useful for the manipulation of the superfluid order parameter in cold Fermi gases.

UR - http://www.scopus.com/inward/record.url?scp=79961105200&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79961105200&partnerID=8YFLogxK

U2 - 10.1103/PhysRevA.84.013609

DO - 10.1103/PhysRevA.84.013609

M3 - Article

VL - 84

JO - Physical Review A

JF - Physical Review A

SN - 2469-9926

IS - 1

M1 - 013609

ER -