A universal lower bound on the free energy cost of molecular measurements

TL;DR

This paper establishes a fundamental lower bound on the free energy cost of molecular measurements in cells, linking it to mutual information and independent of receptor architecture.

Contribution

It proves a universal lower bound on free energy consumption for molecular measurements based solely on signal properties, regardless of receptor design.

Findings

Free energy cost is bounded below by mutual information.

The bound is independent of receptor architecture.

The result applies generally to molecular information processing.

Abstract

The living cell uses a variety of molecular receptors to read and process chemical signals that vary in space and time. We model the dynamics of such molecular level measurements as Markov processes in steady state, with a coupling between the receptor and the signal. We prove exactly that, when the the signal dynamics is not perturbed by the receptors, the free energy consumed by the measurement process is lower bounded by a quantity proportional to the mutual information. Our result is completely independent of the receptor architecture and dependent on signal properties alone, and therefore holds as a general principle for molecular information processing.