Goldstone modes in Larkin-Ovchinnikov-Fulde-Ferrell superconductors

TL;DR

This paper investigates the Goldstone modes arising from spontaneous symmetry breaking in nonuniform LOFF superconductors, deriving their energies and calculating physical properties like superfluid density and elastic modulus.

Contribution

It provides the first general expressions for the energies of phase and elastic Goldstone modes in LOFF superconductors and applies them to a one-dimensional case.

Findings

Derived formulas for Goldstone mode energies.

Calculated superfluid density at low temperatures.

Determined elastic modulus for a 1D LOFF superconductor.

Abstract

In nonuniform Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) superconductors, both the gauge symmetry and the continuous translational symmetry of the normal state are spontaneously broken. This leads to additional bosonic excitations, or Goldstone modes, corresponding to the deformations of the order parameter amplitude modulation in real space. We derive general expressions for the energy of the phase and elastic Goldstone modes. As an example, the superfluid density and the elastic modulus of a one-dimensional LOFF superconductor are calculated at low temperatures.