From Non-normalizable Boltzmann-Gibbs statistics to infinite-ergodic theory

TL;DR

This paper explores the connection between non-normalizable Boltzmann-Gibbs states and infinite-ergodic theory, providing a framework for understanding systems with non-standard thermal states and deriving a new out-of-equilibrium ensemble.

Contribution

It introduces a canonical-like ensemble based on maximum entropy principles for systems approaching non-normalizable states, extending Boltzmann-Gibbs statistics with infinite-ergodic theory.

Findings

Derived a maximum entropy ensemble for non-normalizable states

Connected infinite-ergodic theory with Boltzmann-Gibbs statistics

Provided insights into ergodicity in non-standard thermal systems

Abstract

We study a particle immersed in a heat bath, in the presence of an external force which decays at least as rapidly as $1/x$, for example a particle interacting with a surface through a Lennard-Jones or a logarithmic potential. As time increases, our system approaches a non-normalizable Boltzmann state. We study observables, such as the energy, which are integrable with respect to this asymptotic thermal state, calculating both time and ensemble averages. We derive a useful canonical-like ensemble which is defined out of equilibrium, using a maximum entropy principle, where the constraints are: normalization, finite averaged energy and a mean-squared displacement which increases linearly with time. Our work merges infinite-ergodic theory with Boltzmann-Gibbs statistics, thus extending the scope of the latter while shedding new light on the concept of ergodicity.