Evolution from BCS to BEC superfluidity in the presence of spin-orbit coupling

TL;DR

This paper explores how spin-orbit coupling influences the crossover from BCS to BEC superfluidity, analyzing thermodynamic properties and proposing spin susceptibility measurement as a detection method.

Contribution

It provides a detailed analysis of thermodynamic properties during the BCS-BEC crossover with spin-orbit coupling, highlighting differences between ERD and RO cases.

Findings

Thermodynamic properties depend on spin-orbit coupling and interaction strength.

Differences between ERD and RO cases are significant in thermodynamic behavior.

Spin susceptibility measurement can detect spin-orbit coupling effects.

Abstract

We discuss the evolution from BCS to BEC superfluids in the presence of spin-orbit coupling, and show that this evolution is just a crossover in the balanced case. The dependence of several thermodynamic properties, such as the chemical potential, order parameter, pressure, entropy, isothermal compressibility and spin susceptibility tensor on the spin-orbit coupling and interaction parameter at low temperatures are analyzed. We studied both the case of equal Rashba and Dresselhaus (ERD) and the Rashba-only (RO) spin-orbit coupling. Comparisons between the two cases reveal several striking differences in the corresponding thermodynamic quantities. Finally we propose measuring the spin susceptibility as a means to detect the spin-orbit coupling effect.