Survival of parity effects in superconducting grains at finite temperature

TL;DR

This paper investigates how finite temperature affects superconducting properties in small grains, using quantum Monte Carlo simulations to analyze pairing and thermodynamic behaviors.

Contribution

It introduces an exact quantum Monte Carlo method for simulating finite-temperature superconducting grains of arbitrary size and level spacing.

Findings

Finite size and temperature significantly influence pairing correlations.

The method accurately captures thermodynamic quantities like heat capacity and spin susceptibility.

Results reveal the persistence of parity effects at finite temperatures.

Abstract

We study the thermodynamics of a small, isolated superconducting grain using a recently developed quantum Monte Carlo method. This method allows us to simulate grains at any finite temperature and with any level spacing in an exact way. We focus on the pairing energy, pairing gap, condensation energy, heat capacity and spin susceptibility to describe the grain. We discuss the interplay between finite size (mesoscopic system), pairing correlations and temperature in full detail.