Violations of the second law of thermodynamics by a non completely positive dynamics

TL;DR

This paper demonstrates that using a non-completely positive dynamics to model an open quantum system can violate the second law of thermodynamics, highlighting the importance of complete positivity in physical models.

Contribution

It provides a concrete example where non-completely positive dynamics conflict with thermodynamic principles in an experimentally relevant quantum system.

Findings

Non-completely positive dynamics can lead to violations of the second law.

The studied quantum microcircuit model exemplifies this conflict.

Complete positivity is essential for physically consistent quantum dynamics.

Abstract

We consider a recently proposed model of driven open quantum microcircuit [F. Pellegrini et al., Phys. Rev. Lett. 107, 060401 (2011)] amenable to experimental investigations. We show that such an open quantum system provides a concrete physical instance where to prove that modeling its time-evolution with a dynamics lacking complete positivity conflicts with the second law of thermodynamics.