Physical meaning of nonextensive term in Massieu functions

TL;DR

This paper investigates the role of nonextensive terms in Massieu functions, linking them to thermodynamic fluctuations and demonstrating their significance in finite-size systems through numerical simulations.

Contribution

It introduces a general approach connecting nonextensive terms in Massieu functions to thermodynamic fluctuations, applicable across various physical systems.

Findings

Nonextensive terms can dominate finite-size corrections in Massieu functions.

Numerical simulations confirm the theoretical link between nonextensive terms and fluctuations.

Results are demonstrated on hard sphere, hard disk fluids, and spin lattice systems.

Abstract

In this paper we explore the significance of nonextensive terms in Massieu functions. Finite-size effects are in many cases dominated by a term proportional to the surface area. Nevertheless, in numerical simulations of finite systems with periodic boundary conditions, the nonextensive term can become the dominant correction to Massieu functions. This paper presents a general approach linking these nonextensive terms to thermodynamic fluctuations, demonstrating that equations of state inherently encode this information. Numerical simulations corroborate our results. The examples used are hard sphere and hard disk fluids and a one-dimensional spin lattice, emphasizing the applicability of the results across different classes of systems.