Postponing entanglement sudden death by quantum interferences

Abstract

We investigate the entanglement dynamics in a 2 ⨂ 3 quantum system consisting of a two-level atom and a three-level V-type atom interacting independently with their environments. Pure and mixed initial states, including one-parameter and two-parameter states of the atoms are analyzed. It is observed that the entanglement in the qubit-qutrit system disappears in a finite time, commonly referred to as ESD (entanglement sudden death). We analytically calculate the ESD time using the negativity as an entanglement measure. Remarkably, the presence of vacuum-induced coherence in the three-level atom (qutrit) delays the occurrence of ESD and effectively protects the entanglement from decoherence.