Sudden vanishing and reappearance of nonclassical effects: General occurrence of finite-time decays and periodic vanishings of nonclassicality and entanglement witnesses

TL;DR

This paper explores the universal occurrence of finite-time decays and periodic vanishings of nonclassical effects, such as entanglement and nonclassicality witnesses, across various quantum systems and conditions.

Contribution

It demonstrates that sudden vanishings and reappearances of nonclassical effects are universal phenomena observable in diverse quantum systems beyond entanglement.

Findings

Finite-time decay of nonclassical correlations occurs in various systems.

Periodic vanishings of nonclassicality are not limited to dissipative systems.

Vanishing and reappearance times differ from those of entanglement sudden death.

Abstract

Analyses of phenomena exhibiting finite-time decay of quantum entanglement have recently attracted considerable attention. Such decay is often referred to as sudden vanishing (or sudden death) of entanglement, which can be followed by its sudden reappearance (or sudden rebirth). We analyze various finite-time decays (for dissipative systems) and analogous periodic vanishings (for unitary systems) of nonclassical correlations as described by violations of classical inequalities and the corresponding nonclassicality witnesses (or quantumness witnesses), which are not necessarily entanglement witnesses. We show that these sudden vanishings are universal phenomena and can be observed: (i) not only for two- or multi-mode but also for single-mode nonclassical fields, (ii) not solely for dissipative systems, and (iii) at evolution times which are usually different from those of sudden vanishings and reappearances of quantum entanglement.