Sudden Death and Birth of Entanglement Effects for Kerr-Nonlinear Coupler

TL;DR

This paper investigates the entanglement dynamics in a Kerr-nonlinear coupler interacting with environments, revealing phenomena like sudden death and birth of entanglement in various quantum systems.

Contribution

It demonstrates the occurrence of entanglement sudden death and birth phenomena in Kerr couplers coupled to thermal reservoirs, extending understanding to 2-qubit and 2x3 systems.

Findings

Entanglement exhibits regular oscillations with decreasing amplitude in thermal vacuum environments.

Dark periods and sudden death of entanglement occur with thermal reservoirs.

Entanglement can be rebuilt after death in both 2-qubit and 2x3 systems.

Abstract

We analyse the entanglement dynamics in a nonlinear Kerr-like coupler interacting with external environment. Whenever the reservoir is in a thermal vacuum state the entanglement (measured by concurrence for a two-qubit system) exhibits regular oscillations of decreasing amplitude. In contrast, for thermal reservoirs we can observe dark periods in concurrence oscillations (which can be called a "sudden death" of the entanglement) and the entanglement rebuild (which can be named the "sudden birth" of entanglement). We show that these features can be observed when we deal with 2-qubit system as well as $2\otimes 3$ system.