Titre : Paradox of entropy: a bit of Information without energy
Auteurs : Jean Argouarc’h,
Revue : Entropy: Thermodynamics – Energy – Environment – Economy
Numéro : Issue 1
Volume : 3
Date : 2022/06/27
DOI : 10.21494/ISTE.OP.2022.0868
ISSN : 2634-1476
Résumé : Physical systems materializing a bit of memory have recently been the subject of experiments to explore the link between information and entropy or to realize Maxwell’s demons. Whether microscopic (single electron, molecule) or mesoscopic (glass bead, colloidal particle, nano-magnet) systems, their changes of state are the result of elementary transitions caused by thermodynamic fluctuations or by quantum tunnelling. From the probabilistic equations of these transitions we deduce directly the formulas of energy exchanges between the memory, the energy source which controls its state and the thermostat which surrounds it, avoiding a detour by the theory of information. The resulting theory explains all the experimental results of bistable and tilt memories. In particular, it shows a partial decoupling between the work provided by the energy source and the heat exchanged with the thermostat during the change of state, as well as the influence of the speed of operations on the energies involved and on the thermal dissipation. It brings to light the paradox of the temporality of entropy, which had been evoked by Landau and Lifshitz, namely that entropy is not independent of time, more precisely that the value of entropy at this energy scale depends on the duration retained for its evaluation. It explains why it is possible to create or to delete a bit of information with an energy well below Kb T log2, the Landauer limit, and it completely solves the enigma of the Szilard’s machine.
Éditeur : ISTE OpenScience