Sudden birth and death of entanglement of two atoms in a finite temperature reservoir

Abstract

We discuss the evolution of entanglement for a system of two two-level atoms interacting with a common reservoir at finite temperature. The Markovian master equation is used to describe the evolution of entanglement measured by concurrence. The phenomena of sudden birth and sudden death of entanglement are discussed. It is shown that entanglement sudden death is a standard feature when the reservoir has finite temperature. Entanglement sudden birth, which is the result of the collective behaviour of atoms, appears only for a sufficiently small mean number of photons of the reservoir (sufficiently low temperatures), and it gradually diminishes as the temperature increases. The results are illustrated for the system prepared in the Werner state.