Fluctuation relations for irreversible emergence of information

Abstract

Information theory and Thermodynamics have developed closer in the last years, with a growing application palette in which the formal equivalence between the Shannon and Gibbs entropies is exploited. The main barrier to connect both disciplines is the fact that information does not imply a dynamics, whereas thermodynamic systems unfold with time, often away from equilibrium. Here, we analyze chain-like systems comprising linear sequences of physical objects carrying symbolic meaning. We show that, after defining a reading direction, both reversible and irreversible informations emerge naturally from the principle of microscopic reversibility in the evolution of the chains driven by a protocol. We find fluctuation equalities that relate entropy, the relevant concept in communication, and energy, the thermodynamically significant quantity, examined along sequences whose content evolves under writing and revision protocols. Our results are applicable to nanoscale chains, where information transfer is subject to thermal noise, and extendable to virtually any communication system.

Harnessing Maxwell’s demon to establish a macroscale concentration gradient

“…Our demon can thus be considered as a simple machine, whereby passage through a gate is regulated by changing the state of a molecule 21,24,[37][38][39][40][41][42][43][44][45][46][47][48] . This type of demon has been described in terms of an energy ratchet [49][50][51] or, in analogy with a system filled with flying umbrellas, divided into two compartments using a barrier containing evenly spaced bars 52 .…”