Quantum correlations in non-Markovian open quantum systems at different ranges of temperature

Abstract

In this paper, we numerically explore the quantum correlations in a system consisting of two identical qubits, each of them locally interacting with a bosonic reservoir under non-Markovian regime, dissipative quantum system. The influences of Ohmic reservoir with Lorentz–Drude regularization on the quantum discord and entanglement are studied. We analyze the quantum correlations rate in high temperature, intermediate temperature, and low temperature reservoirs, respectively. The dependence of the quantum correlations on the ratio r of the reservoir cutoff frequency and the system oscillator frequency, and temperature kBT shows that the decreasing of the frequency ratio r enhances the amount of quantum correlations between the two qubits, while the increasing of the temperature damages the amount of correlations. More precisely, we find a sudden death of quantum entanglement, that is, the entanglement vanishes as time becomes large for different temperatures. On the other hand, we show in contrast to what happens to entanglement, the quantum discord does not vanish even at high temperatures.