On the thermodynamic analogy of intracellular diffusivity fluctuations

TL;DR

This paper explores a thermodynamic analogy for intracellular diffusivity fluctuations, identifying thermodynamic quantities and constructing an analog of a heat engine with Carnot efficiency.

Contribution

It introduces a formal thermodynamic framework for diffusivity fluctuations, including an analog of the Carnot engine and entropy considerations.

Findings

Constructed an analog of the heat engine for diffusivity fluctuations.

Identified thermodynamic quantities such as heat, work, and internal energy in the context of diffusivity.

Demonstrated that the efficiency of this analog engine is formally equivalent to the Carnot engine.

Abstract

Two recent topics on a formal thermodynamic analogy of intracellular diffusivity fluctuations observed experimentally in normal/anomalous diffusion are reported. Not only the analogs of the quantity of heat and work as well as the internal energy but also that of the Clausius inequality are identified. Then, the analog of the heat engine is constructed to characterize extraction of the diffusivity change as the analog of work during a cycle, the efficiency of which is formally equivalent to that of the Carnot engine, making the total change of the entropy concerning the fluctuations vanish. The effect of the slow variation of the fluctuations on the efficiency is also briefly discussed.