Fluctuation corrections on thermodynamic functions: Finite size effect

TL;DR

This paper investigates how finite size effects and dissipation influence thermodynamic functions, especially the specific heat, in a spin system interacting with a spin bath, revealing abrupt transitions linked to dynamical factors.

Contribution

It introduces a method to explicitly calculate thermodynamic functions considering finite size and dissipation effects, highlighting the role of dynamical correction factors.

Findings

Specific heat is expressed as a product of thermal and dynamical factors.

Finite size induces abrupt transitions in specific heat with temperature.

Dissipative interactions significantly alter thermodynamic behavior.

Abstract

The explicit thermodynamic functions, in particular, the specific heat of a spin system interacting with a spin bath which exerts finite dissipation on the system are determined. We show that the specific heat is a sum of the products of a thermal equilibration factor that carries the temperature dependence and a dynamical correction factor, characteristic of the dissipative energy flow under steady state from the system. The variation of specific heat with temperature is accompanied by an abrupt transition that depends on these dynamical factors characteristic of the finite system size.