The University of Southampton
University of Southampton Institutional Repository

Superfluid pairing between fermions with unequal masses

Superfluid pairing between fermions with unequal masses
Superfluid pairing between fermions with unequal masses
We consider a superfluid state in a two-component gas of fermionic atoms with equal densities and unequal masses in the BCS limit. We develop a perturbation theory along the lines proposed by Gorkov and Melik-Barkhudarov and find that for a large difference in the masses of heavy (M) and light (m) atoms one has to take into account both the second-order and third-order contributions. The result for the critical temperature and order parameter is then quite different from the prediction of the simple BCS approach. Moreover, the small parameter of the theory turns out to be (pF?a???)?M?m?1, where pF is the Fermi momentum and a the scattering length. Thus, for a large mass ratio M?m the conventional perturbation theory requires significantly smaller Fermi momenta (densities) or scattering lengths than in the case of M?m, where the small parameter is pF?a????1. We show that three-body scattering resonances appearing at a large mass ratio due to the presence of three-body bound Efimov states do not influence the result, which in this sense becomes universal.
1050-2947
033620-[16pp]
Baranov, M.A.
18a02c81-a6a1-4603-9d66-d570fbbd581e
Lobo, C.
cde7843a-c00b-4242-a8cd-1abb2dfe0703
Shlyapnikov, G.V.
30eeeb7f-06fa-4853-8820-eae523f4e43b
Baranov, M.A.
18a02c81-a6a1-4603-9d66-d570fbbd581e
Lobo, C.
cde7843a-c00b-4242-a8cd-1abb2dfe0703
Shlyapnikov, G.V.
30eeeb7f-06fa-4853-8820-eae523f4e43b

Baranov, M.A., Lobo, C. and Shlyapnikov, G.V. (2008) Superfluid pairing between fermions with unequal masses. Physical Review A, 78 (3), 033620-[16pp]. (doi:10.1103/PhysRevA.78.033620).

Record type: Article

Abstract

We consider a superfluid state in a two-component gas of fermionic atoms with equal densities and unequal masses in the BCS limit. We develop a perturbation theory along the lines proposed by Gorkov and Melik-Barkhudarov and find that for a large difference in the masses of heavy (M) and light (m) atoms one has to take into account both the second-order and third-order contributions. The result for the critical temperature and order parameter is then quite different from the prediction of the simple BCS approach. Moreover, the small parameter of the theory turns out to be (pF?a???)?M?m?1, where pF is the Fermi momentum and a the scattering length. Thus, for a large mass ratio M?m the conventional perturbation theory requires significantly smaller Fermi momenta (densities) or scattering lengths than in the case of M?m, where the small parameter is pF?a????1. We show that three-body scattering resonances appearing at a large mass ratio due to the presence of three-body bound Efimov states do not influence the result, which in this sense becomes universal.

Text
PhysRevA_78_033620.pdf - Version of Record
Restricted to Repository staff only
Request a copy

More information

Published date: 29 September 2008
Organisations: Mathematics

Identifiers

Local EPrints ID: 156293
URI: https://eprints.soton.ac.uk/id/eprint/156293
ISSN: 1050-2947
PURE UUID: 6b1a8e08-ed29-42de-a08d-31f42bc8b229
ORCID for C. Lobo: ORCID iD orcid.org/0000-0001-7060-3905

Catalogue record

Date deposited: 01 Jun 2010 08:49
Last modified: 29 Oct 2019 01:45

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×