Theoretical Study Of Quantum Batteries Based On Superconducting Circuits

As electrical devices become more precise and miniaturized,traditional batteries,designed and manufactured based on classical physics,are gradually unable to meet human needs.People have begun to consider whether a new energy storage device with performance superior to traditional batteries can be designed.Thus,the concept of quantum batteries(QBs)emerged and related research has become a cutting-edge topic in the field of quantum physics.There are many quantum systems that can be used to realize QBs,such as ion trap systems,NV center systems,quantum dot systems,and superconducting circuit systems.Among them,superconducting circuit systems have advantages such as flexibility,tunability,scalability,and strong coupling with external fields,and have been favored by researchers for their important theoretical significance and practical value in achieving QBs in the future.Some experimental works have shown that three-level quantum battery(QB)can be realized based on superconducting circuit systems.This type of QB can be stably charged,but its energy storage is very limited.Therefore,it is crucial to explore many-body QBs that can store more energy and charge faster.This thesis proposes theoretical schemes for implementing two types of many-body QBs(resonator-qubits QB and resonator-qutrits QB)based on the superconducting circuit platform and explores the performance of these two QBs in the presence of environment.Firstly,we investigate the resonator-qubits QB.A superconducting circuit system composed of N capacitively coupled Transmons and a one-dimensional transmission line resonator was constructed,and its Hamiltonian was derived.When the anharmonicity of Transmon is much larger than the detuning between the resonator and Transmon,the resonator-qubits QB is defined,and the influence of the environment on its charging performance is explored.The results show that the presence of decay channels suppresses the highly oscillatory phenomenon during the charging process,thereby achieving stable charging of the resonator-qubits QB.Compared with the resonator decay and the qubit relaxation,the qubit dephasing shows a counterintuitive advantage in our resonator-qubits QB.In addition,we also demonstrate the feasibility of our approach by evaluating the performance of resonator-qubits QB under experimental parameters.The results lay a theoretical foundation for realizing stable and efficient resonator-qubits QB.Secondly,we investigate the resonator-qutrits QB.When the anharmonicity of Transmon is relatively small,the resonator-qutrits QB is defined,and the important roles of the environment on its charging performance as well as the dephasing process and energy gap of the quantum qutrits on its self-discharging process are revealed.The results show that the collective behavior between the resonator-qutrits QB and the environment will eventually lead to the charging process of the resonator-qutrits QB reaching a steady state;by adjusting the coupling strength between the resonator and quantum qutrits,the charging performance of the resonator-qutrits QB can be further optimized;considering the dephasing process of the quantum qutrits and changing its energy gap will reduce the speed of the resonator-qutrits QB’s self-discharging.The results provide theoretical support for realization of the resonator-qutrits QB with large capacity and slow self-discharging.