Application And Research Of Quantum Coherence In Open Quantum Battery

The storage and release of energy in quantum battery primarily relies on the transition of atoms between energy levels.Optimizing the charging performance of quantum battery by utilizing quantum effects such as coherence or entanglement could enable the realization of high-power,atomic-sized,large-capacity battery devices.Thus,the design theory of high-performance quantum battery has become a crucial area of focus in the field of thermodynamics.As all systems unavoidably interact with the environment,the investigation of charging and discharging characteristics of open quantum battery has attracted scholars’ attention.Quantum coherence and entanglement,unique phenomena in quantum systems,have demonstrated their importance in various areas such as quantum computing,communication,energy transmission,and regulation.In this paper,based on the collision model framework,we present two open quantum battery charging models to study the impact of interaction strength,quantum coherence and battery size on the charging performance of quantum battery.The main research work of this paper is as follows:(1)An open quantum battery model for charging multi-level quantum systems under the coherent auxiliary bath composed of an ensemble of atom pairs is constructed,and the impact of quantum coherence(coherence strength and coherent phase)in the environment,the interaction strength between the battery and the environment,and the influence of battery size on battery capacity(maximum extractable work),charging speed(power)and efficiency are studied.The findings demonstrate that the coherence of the auxiliary bath leads to oscillatory behavior in the maximum extractable work of the quantum battery during charging.Meanwhile,the local phase difference between two atoms in the auxiliary bath is also an important parameter that affects the performance of quantum battery,significantly impacting the steady-state maximum extractable work and charging power of the quantum battery.The research analyzes and determines optimal implementation schemes of short-term fast charging and long-term large-capacity charging modes of multi-energy-level quantum battery,considering its performance characteristics.Finally,the study investigates the effect of battery size on the charging performance of quantum battery and indicates that under short-time charging protocols,charging power and efficiency of quantum battery are positively correlated with size.(2)A quantum battery model for charging a single-qubit system under the V-shaped three-level auxiliary bath is constructed,and the master equation of the quantum battery is derived under the collision charging protocol,and the solution of the equation was obtained.The study focuses on the characteristics of the maximum extractable work in the steady state(when fully charged)of the quantum battery.The analysis reveals that the maximum extractable work in the steady state is made up of two parts: the steady state internal energy and the entropy of the battery system.Furthermore,both of these contributions are related to the temperature of the environment,with the energy contribution dominating in the low temperature region and the entropy contribution dominating in the high temperature region.The research also investigates the impact of the ancilla’s degenerate coherence and the interaction strength between the battery and the ancilla on the maximum extractable work.