Propagation of irreversibility to macroscopic scales

Determine the quantitative extent to which irreversibility generated by microscopic dissipative processes in far-from-equilibrium biological systems can persist at macroscopic scales under coarse-grained descriptions of the dynamics.

Background

The paper emphasizes that biological systems dissipate energy at microscopic scales through irreversible processes, which in turn drive functions at larger scales. Despite this understanding, the authors note that it is not established how much of the microscopic irreversibility can survive at macroscopic levels of description.

They develop a model-free coarse-graining framework designed to minimize loss of irreversibility and apply it to diverse systems, including molecular motors, biochemical oscillators, and neural activity. While these case studies show substantial preservation of irreversibility, the general limits on its propagation across scales remain to be characterized.

References

Yet despite the clear generation of nonequilibrium dynamics at small scales, it remains unclear how much irreversibility can propagate to large scales.

— Coarse-graining dynamics to maximize irreversibility  (2506.01909 - Yu et al., 2 Jun 2025) in Introduction

This viewpoint raises several important questions for future work. Under which conditions does nonreciprocity survive coarse-graining and leave macroscopic traces? Which indicators of broken time-reversal symmetry remain robust across scales?

— When does nonreciprocity matter? Scale-dependence and nonequilibrium signatures  (2609.08820 - Loos et al., 8 Sep 2026) in Conclusions