Yu Wen-Li, Zhang Yun, Li Hai, Wei Guang-Fen, Han Li-Ping, Tian Feng, Zou Jian. Enhancement of charging performance of quantum battery via quantum coherence of bath[J]. JOURNAL OF MECHANICAL ENGINEERING, 2023, 32(1): 010302. doi: 10.1088/1674-1056/ac728b
Citation:
Yu Wen-Li, Zhang Yun, Li Hai, Wei Guang-Fen, Han Li-Ping, Tian Feng, Zou Jian. Enhancement of charging performance of quantum battery via quantum coherence of bath[J]. JOURNAL OF MECHANICAL ENGINEERING, 2023, 32(1): 010302. doi: 10.1088/1674-1056/ac728b
Yu Wen-Li, Zhang Yun, Li Hai, Wei Guang-Fen, Han Li-Ping, Tian Feng, Zou Jian. Enhancement of charging performance of quantum battery via quantum coherence of bath[J]. JOURNAL OF MECHANICAL ENGINEERING, 2023, 32(1): 010302. doi: 10.1088/1674-1056/ac728b
Citation:
Yu Wen-Li, Zhang Yun, Li Hai, Wei Guang-Fen, Han Li-Ping, Tian Feng, Zou Jian. Enhancement of charging performance of quantum battery via quantum coherence of bath[J]. JOURNAL OF MECHANICAL ENGINEERING, 2023, 32(1): 010302. doi: 10.1088/1674-1056/ac728b
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.
Fig. 1..
Sketch of charging protocol of open quantum battery (QB). The charging process of battery (a single-qubit system) is mimicked by a series of two-level atoms (TLAs) as auxiliary units (or ancillae labeled by Ai with state ρA) coupling to the battery one by one. We assumes that each ancilla only interacts with the battery once, and the time-independent interaction V between the ancilla and the battery lasts for time τ for each ancilla. denotes the state of the ancilla after interacting with the battery. The thermal (coherent) QB without (with) coherence can be formed when the thermal (coherent) ancillae with ancilla’s state ρA = ρth (thermal state) (ρA = ρcoh (coherent state)) are considered.
Fig. 2..
(a) MEW as a function of coherence magnitude α and coupling strength δ,with parametric space of coupling strength divided into three regimes by the pink solid line with δ = 1.28 and the blue solid line δ = 1.4, that is, I: 0 < δ ≲ 1.28, II: 1.28 < δ < 1.4 and III: 1.4δ ≤ 5, and with MEW varying with α for δ = {0.1,0.3,0.5,1} (regime I) and δ = {3,5} (regime III) in (b), and δ = {1.28,1.32,1.36,1.40} (regime II) in panel (c). The other parameters are τ = 0.005, and w = 1.5.
Fig. 3..
Variations of MEW Wmax with charging step n corresponding to charging time tn = nτ for (a) some fixed weak coupling δ = {0.1,0.2,0.3,0.4,0.5} and (b) some strong coupling δ = {1,2,3,4,5} for CAB (α = 1), and for panel (c) TAB (α = 0) and δ = {0.1,0.3,0.5,1,3,5}. The other parameters are the same as those in Fig. 2.
Fig. 4..
(a) Comparisons of MEWs of QB in full charging and at the first peak time tPeak, and , when TAB (α = 0) and CAB (α = 1) are considered, respectively. (b) Variations of charging saturation of QB at charging time tPeak, () with coupling strength δ for TAB and CAB. The other parameters are the same as those in Fig. 2.
Fig. 5..
Curve of average charging power versus δ of QB with the CAB (α = 1) and the TAB (α = 0) for QB charging to approximate saturation with charging time tf = Tcoh for (a) CAB and tf = Tth for TAB satisfying R(Tcoh,th) = 99%, and (b) the first peak time tf = tPeak. The other parameters are the same as those in Fig. 2.
Fig. 6..
Curves for efficiencies and ( and ) versus coupling strength δ of QB assisted with CAB (α = 1) and the TAB (α = 0) in full charging (short-time charging tf = tPeak) process. The other parameters are the same as those in Fig. 2.
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