Decay of a quasi-stable quantum system and quantum backflow

TL;DR

This paper explores the phenomenon of quantum backflow during the decay of quasi-stable systems and in free wave packets, revealing inward probability currents during certain decay phases.

Contribution

It establishes a connection between quantum backflow and the inward probability current during the decay transition, and demonstrates substantial backflow in free wave packets.

Findings

Inward probability current occurs during the transition from exponential to inverse-power-law decay.

Quantum backflow is associated with small inward probability flows in decaying systems.

Significant backflow is observed in initially confined free wave packets.

Abstract

The decay of quasi-stable quantum system involves primarily an outgoing probability current density. However, during the transition from exponential to inverse-power-law decay there are time intervals during which this current, although small, is inward. In this paper this inward flow is associated with quantum backflow. Furthermore substantial backflow exists for time-evolving free wave packets which are initially confined in space.