# Universal thermodynamic bounds on nonequilibrium response with biochemical applications

## TL;DR

This paper derives universal thermodynamic bounds that constrain the response of nonequilibrium systems, extending fluctuation-dissipation concepts far from equilibrium, with applications to biochemical systems.

## Contribution

It introduces a set of equalities and inequalities that apply to nonequilibrium steady states, providing new tools to analyze their response characteristics.

## Key findings

- Bounds on nonequilibrium response derived
- Application to biochemical motifs demonstrated
- Framework extends fluctuation-dissipation relations

## Abstract

Diverse physical systems are characterized by their response to small perturbations. Near thermodynamic equilibrium, the fluctuation-dissipation theorem provides a powerful theoretical and experimental tool to determine the nature of response by observing spontaneous equilibrium fluctuations. In this spirit, we derive here a collection of equalities and inequalities valid arbitrarily far from equilibrium that constrain the response of nonequilibrium steady states in terms of the strength of nonequilibrium driving. Our work opens new avenues for characterizing nonequilibrium response. As illustrations, we show how our results rationalize the energetic requirements of two common biochemical motifs.