Unified Approach to Classical Speed Limit and Thermodynamic Uncertainty Relation

TL;DR

This paper introduces a universal lower bound on entropy production that unifies classical speed limits and thermodynamic uncertainty relations, providing tighter constraints and extending applicability to systems with broken time-reversal symmetry.

Contribution

The authors derive a universal entropy production bound that unifies and tightens classical speed limits and thermodynamic uncertainty relations, applicable to a broad class of thermodynamic systems.

Findings

Universal lower bound on entropy production derived.

Tighter classical speed limit than previous bounds.

Generalized thermodynamic uncertainty relation established.

Abstract

The total entropy production quantifies the extent of irreversibility in thermodynamic systems, which is nonnegative for any feasible dynamics. When additional information such as the initial and final states or moments of an observable is available, it is known that tighter lower bounds on the entropy production exist according to the classical speed limits and the thermodynamic uncertainty relations. Here, we obtain a universal lower bound on the total entropy production in terms of probability distributions of an observable in the time forward and backward processes. For a particular case, we show that our universal relation reduces to a classical speed limit, imposing a constraint on the speed of the system's evolution in terms of the Hatano--Sasa entropy production. Notably, the newly obtained classical speed limit is tighter than the previously reported bound by a constant factor. Moreover, we demonstrate that a generalized thermodynamic uncertainty relation can be derived from another particular case of the universal relation. Our new uncertainty relation holds for systems with time-reversal symmetry breaking and recovers several existing bounds. Our approach provides a unified perspective on two closely related classes of inequality: classical speed limits and thermodynamic uncertainty relations.