Spin imbalance effect on Larkin-Ovchinnikov-Fulde-Ferrel state

TL;DR

This paper investigates how spin imbalance influences the LOFF state in superconductors and ultracold Fermi gases, providing exact solutions for condensates and fermion spectra under various imbalance conditions.

Contribution

It offers the first exact solutions for condensates and fermion spectra with arbitrary spin imbalance in LOFF states, including fermion zero modes.

Findings

Exact solutions for condensates with arbitrary spin imbalance

Perturbative fermion spectrum analysis under small imbalance

Exact fermion zero mode solution

Abstract

We study spin imbalance effects on the Larkin-Ovchinikov-Fulde-Ferrel (LOFF) state relevant for superconductors under a strong magnetic field and spin polarized ultracold Fermi gas. We obtain the exact solution for the condensates with arbitrary spin imbalance and the fermion spectrum perturbatively in the presence of small spin imbalance. We also obtain fermion zero mode exactly without perturbation.