In-vivo entropy production of A. subaru

TL;DR

This paper investigates entropy production in a macroscopic biological system, showing it provides a loose lower bound on energy consumption and introducing a new kNN estimator for irreversibility.

Contribution

It applies entropy estimation tools to a macroscopic system with known energy use and develops a novel kNN estimator for irreversibility measurement.

Findings

Entropy production underestimates true energy consumption by about 25 orders of magnitude.

Different irreversibility estimation methods were surveyed and compared.

A new kNN estimator for irreversibility was introduced.

Abstract

Entropy production is often used as a proxy for energy consumption of a non-equilibrium system. Lower bounds can be estimated from coarse-grained observations, and this has been done for various biological systems. Here, we apply these tools to a more macroscopic system whose true energy consumption is also known. We find that while entropy production does give a lower bound, it is some 25 orders of magnitude away from being saturated. To be certain of this result, we survey different methods of estimating irreversibility, and write down a novel kNN estimator.