Steady state thermodynamics

TL;DR

This paper introduces steady state thermodynamics (SST), a new framework aiming to describe a wide range of nonequilibrium steady states through operationally defined thermodynamic quantities, leading to novel predictions testable experimentally.

Contribution

It develops a universal thermodynamic formalism for nonequilibrium steady states, extending classical concepts and making experimentally verifiable predictions.

Findings

Extension of Einstein's density fluctuation formula

Extension of the minimum work principle

Prediction of a nonequilibrium osmotic pressure

Abstract

The present paper reports our attempt to search for a new universal framework in nonequilibrium physics. We propose a thermodynamic formalism that is expected to apply to a large class of nonequilibrium steady states including a heat conducting fluid, a sheared fluid, and an electrically conducting fluid. We call our theory steady state thermodynamics (SST) after Oono and Paniconi's original proposal. The construction of SST is based on a careful examination of how the basic notions in thermodynamics should be modified in nonequilibrium steady states. We define all thermodynamic quantities through operational procedures which can be (in principle) realized experimentally. Based on SST thus constructed, we make some nontrivial predictions, including an extension of Einstein's formula on density fluctuation, an extension of the minimum work principle, the existence of a new osmotic pressure of a purely nonequilibrium origin, and a shift of coexistence temperature. All these predictions may be checked experimentally to test SST for its quantitative validity.