Quantum correlations between each qubit in a two-atom system and the environment in terms of interatomic distance

摘要

The quantum correlations between a qubit and its environment are describedquantitatively in terms of interatomic distance. Specifically, considering arealistic system of two two-level atoms and taking into account thedipole-dipole interaction and collective damping, the quantum entanglement andquantum discord are investigated, during the dissipative process, as a functionof the interatomic distance. For atoms that are initially maximally entangled,it turns out that there is a critical distance where each atom is maximallyquantum correlated with its environment. Counterintuitively, the approach ofthe two atoms can maximize the entanglement between each one and theenvironment and, even at the same distance, minimize the loss of entanglementbetween the pair.