Quantum memory as a perpetuum mobile? Stability v.s. reversibility of information processing

TL;DR

The paper presents a thought experiment suggesting that scalable quantum memory could violate thermodynamic principles, challenging the feasibility of such systems due to stability and reversibility constraints.

Contribution

It proposes a modified Landauer's principle for metastable states, linking thermodynamics and quantum information processing.

Findings

Quantum memory could act as a perpetuum mobile under certain assumptions

Changing metastable states involves energy dissipation proportional to stability

Identification of metastable states can be done with minimal energy cost

Abstract

It is argued using a Gedankenexperiment that a scalable quantum memory could be used as a perpetuum mobile of the second kind and hence cannot be realized in Nature. The reasoning is based on the assumption that the Landauer's principle for measurements is a consequence of the second law of thermodynamics and not an independent postulate. This implies a modification of the Landauer's principle when applied for discrimination of equilibrium (metastable) states. While identification of the metastable state can be done at the infinitesimally low cost, a change of such a state involves dissipation of energy proportional to its stability factor.