Enhancement of charging performance of quantum battery via quantum coherence of bath

Abstract

An open quantum battery (QB) model of a single qubit system charging in a coherent auxiliary bath (CAB) consisting of a series of independent coherent ancillae is considered. According to the collision charging protocol we derive a quantum master equation and obtain the analytical solution of QB in a steady state. We find that the full charging capacity (or the maximal extractable work (MEW)) of QB, in the weak QB-ancilla coupling limit, is positively correlated with the coherence magnitude of ancilla. Combining with the numerical simulations we compare with the charging properties of QB at finite coupling strength, such as the MEW, average charging power and the charging efficiency, when considering the bath to be a thermal auxiliary bath (TAB) and a CAB, respectively. We find that when the QB with CAB, in the weak coupling regime, is in fully charging, both its capacity and charging efficiency can go beyond its classical counterpart, and they increase with the increase of coherence magnitude of ancilla. In addition, the MEW of QB in the regime of relative strong coupling and strong coherent magnitude shows the oscillatory behavior with the charging time increasing, and the first peak value can even be larger than the full charging MEW of QB. This also leads to a much larger average charging power than that of QB with TAB in a short-time charging process. These features suggest that with the help of quantum coherence of CAB it becomes feasible to switch the charging schemes between the long-time slow charging protocol with large capacity and high efficiency and the short-time rapid charging protocol with highly charging power only by adjusting the coupling strength of QB-ancilla. This work clearly demonstrates that the quantum coherence of bath can not only serve as the role of “fuel” of QB to be utilized to improve the QB’s charging performance but also provide an alternative way to integrate the different charging protocols into a single QB.

The application of quantum coherence as a resource

“…proved that the quantum coherence of the bath can be used as the "fuel" of a quantum battery to improve the charging performance of the quantum battery. [155] Charging and discharging power Power is an important parameter for measuring the charge and discharge performance. Charging power is defined as the amount of charging and discharging energy per unit time, that is,…”

Charging performance of quantum batteries based on intensity-dependent Dicke model

“…. Shi等 [23] 详细 研究了量子相干性和量子纠缠等量子资源同量子 电池中提取功之间的关系, 阐明了量子电池中量子 相干性和电池与充电器之间的纠缠是产生非零提 取功的必要条件, 且在充电结束后, 量子相干性促 进了相干功, 而量子相干性和纠缠抑制了非相干 功. 最近, Yu等 [24] 研究了一个开放量子电池中热 库的量子相干性对量子电池中充电性能的影响, 发 现热库中的量子相干性对充电功率、充电容量及充 电效率的改进是有利的.…”