Improving the steady-state coherence and entanglement of two coupled qubits via composite system-reservoir interactions

Abstract

In this work, we study the improvement of steady-state coherence (SSC) and steady-state entanglement (SSE) of two coupled qubits by means of composite system-reservoir interaction constructed by a linear combination of orthogonal and parallel ones. We show that in the non-equilibrium case, the SSC and SSE can be significantly enhanced by increasing the parallel components of the interaction Hamiltonian between the system of interest and the heat reservoirs. In addition, we find that in the non-equilibrium case, increasing the parallel components can enlarge the temperature (temperature difference) region where the SSC can maintain nonzero values. In the equilibrium situation, however, the SSC and SSE are not affected by the parallel components of the composite system-reservoir interactions.

Improving Entanglement Generation Using the Coherence of a Nonthermal Reservoir

“…Hence, exploring effective and practical schemes for entanglement generation, improvement, and protection in open quantum systems is important for applying quantum entanglement and developing quantum technology. In recent decades, numerous protocols [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] have been proposed to generate and enhance quantum entanglement. For example, in refs.…”