库的量子关联相干辅助系统能量提取的研究

基于单模微腔与二能级原子系综(库)构成的混合动力学模型,探索了非平衡库中量子关联相干(quantum correlated coherence, QCC)Tan K C, et al. 2016 Phys. Rev. A 94, 022329])对系统动力学的影响.推导了量子关联相干库下系统演化的动力学方程.借助于含QCC的类GHZ库及其对应的参考库,清晰地揭示了非平衡库中QCC扮演着热力学资源的角色——能够有效辅助系统从库中提取更多能量.同时,结合解析与数值模拟方法研究了类GHZ库的有效温度和系统与库间的耦合参数对QCC能量效应的影响.研究发现, QCC对腔场的能量贡献不仅依赖于库的有效温度,而且也和系统与库间的耦合参数有关.这与二能级原子构成的传统的热库的情况(腔场从热库中提取的能量仅仅依赖于库的有效温度即二能级原子的热布局)完全不同.此外,研究发现QCC可视作一类优质的热力学资源,在特定条件下其对系统的能量贡献远大于原子热布局的贡献.因此, QCC将是高输出功率或高效率量子热机设计中的一类重要燃料.

Study on energy extraction assisted with quantum correlated coherence in bath

Based on a hybrid model of a single-mode microcavity system plus an ensemble of two-level atoms (TLAs), we investigate the effect of quantum correlated coherence (QCC) Tan K C, et al. 2016 Phys. Rev. A 94, 022329] of bath on the dynamic behaviors of system. The dynamic equations of system for a general bath with QCC have been derived. With the help of the GHZ-like state with QCC and its reference state, the role of QCC as a thermodynamic resource has been clearly shown where QCC could be used to enhance the system's energy. Meanwhile, combining with the analytical and numerical simulation methods, the influences of effective temperature of GHZ-like bath and the coupling strength between the system and the bath on the energy effect of QCC have been studied. We find that the energy contribution of QCC to the cavity field relies not only on the effective temperature of bath but also on the coupling strength. That is completely different from the case of traditional thermal bath where the energy captured by the cavity from the bath only depends on the bath temperature, i.e., the thermal distribution of TLAs. Moreover, several interesting phenomena, in the paper, have been shown: 1) the higher of the effective temperature of bath, the larger of the cavity's energy extracted from the QCC of bath; 2) under the fixed effective temperature of bath, the smaller of the coupling strength the larger of the maximal extractable energy from QCC of bath; 3) there exists the trade-off between the cavity's energy and the capability of cavity capturing the energy of TLAs entering the cavity, i.e., the cavity's energy extracted from each TLA crossing the cavity always decreases as the energy of cavity increases; 4) the energy contribution of QCC of bath to cavity is beyond the one of the thermal distribution of TLAs in bath, and it could become more prominent when the coupling strength is taken the smaller value, which also means that in the case of weak coupling strength it is the QCC of bath not the thermal distribution of bath dominating the cavity's energy. Thus, the QCC of bath could be viewed as a kind of high quality thermodynamic resource. It has the potential applications in the design of a quantum engine with high output power or efficiency, and the enhancement of charging speed of quantum battery. Our investigation is beneficial to the further understanding of quantum coherence in quantum thermodynamic regime.