The stochastic limit in the analysis of the open BCS model

TL;DR

This paper demonstrates how the stochastic limit method simplifies the analysis of the open BCS model, accurately determining critical temperature and order parameters more efficiently.

Contribution

It introduces the stochastic limit as a useful perturbative approach for analyzing the open BCS model, streamlining the derivation of key physical quantities.

Findings

Critical temperature matches previous results

Order parameters are obtained with simplified calculations

Stochastic limit proves effective for open quantum systems

Abstract

In this paper we show how the perturbative procedure known as {\em stochastic limit} may be useful in the analysis of the Open BCS model discussed by Buffet and Martin as a spin system interacting with a fermionic reservoir. In particular we show how the same values of the critical temperature and of the order parameters can be found with a significantly simpler approach.