Can Somebody Please Say What Gibbsian Statistical Mechanics Says?

TL;DR

This paper critically examines Gibbsian statistical mechanics, clarifying its ambiguous aspects and proposing a coherent interpretation of the Averaging Principle to better connect theory with experimental practice.

Contribution

It offers a new interpretation of GSM that clarifies the role and scope of the Averaging Principle, resolving longstanding ambiguities.

Findings

Clarifies the ambiguous status of the Averaging Principle in GSM

Provides a coherent interpretation linking GSM to experimental practice

Resolves conceptual difficulties in understanding GSM's claims

Abstract

Gibbsian statistical mechanics (GSM) is the most widely used version of statistical mechanics among working physicists. Yet a closer look at GSM reveals that it is unclear what the theory actually says and how it bears on experimental practice. The root cause of the difficulties is the status of the Averaging Principle, the proposition that what we observe in an experiment is the ensemble average of a phase function. We review different stances toward this principle, and eventually present a coherent interpretation of GSM that provides an account of the status and scope of the principle.