The effects of system–environment correlations on heat transport and quantum entanglement via collision models

By means of collision models, we study the effects of system–environment correlations (SECs) on the heat transport and quantum entanglement in both transient and steady-state regimes. In the considered models, the reservoirs are simulated through two chains of particles whose nearest-neighbor collisions induce the SECs. In the first model, the system is a qubit connecting two independent reservoirs with different temperatures. We show that the heat currents exhibit oscillations and even reversed flows from the cold reservoir to the hot one depending on intracollision strengths of reservoir particles. In the stationary regime, we observe a nonlinear relation between heat currents and intracollision strengths, which can be accounted for by the established steady-state SECs. In our second model, the system contains two interacting qubits and we show that the initial entanglement of the system either vanishes within finite steps of collisions or recovers from disappearing and retains nonzero value. The combined regions of relevant parameters that sustain steady-state entanglement are presented. We also present a method to enhance the steady-state entanglement by enlarging temperature differences of the two reservoirs.