Emergence of PTsymmetry breaking in open quantum systems
Abstract
The effect of PTsymmetry breaking in coupled systems with balanced gain and loss has recently attracted considerable attention and has been demonstrated in various photonic, electrical and mechanical systems in the classical regime. Here we generalize the definition of PT symmetry to finitedimensional open quantum systems, which are described by a Markovian master equation. Specifically, we show that the invariance of this master equation under a certain symmetry transformation implies the existence of stationary states with preserved and broken parity symmetry. As the dimension of the Hilbert space grows, the transition between these two limiting phases becomes increasingly sharp and the classically expected PTsymmetry breaking transition is recovered. This quantumtoclassical correspondence allows us to establish a common theoretical framework to identify and accurately describe PTsymmetry breaking effects in a large variety of physical systems, operated both in the classical and quantum regimes.
 Publication:

SciPost Physics
 Pub Date:
 October 2020
 DOI:
 10.21468/SciPostPhys.9.4.052
 arXiv:
 arXiv:2003.02265
 Bibcode:
 2020ScPP....9...52H
 Keywords:

 Quantum Physics;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Physics  Optics
 EPrint:
 15 pages, 3 figures