Abstract The advantage of quantum batteries is that quantum resources can be utilized to enhance charging efficiency. The known available quantum resources are quantum entanglement and quantum coherence. In this study, quantum steering is introduced as a new quantum resource into batteries for the first time. By considering two models, namely the Field‐quantum battery and the Cavity–Heisenberg quantum battery, the relationship is analyzed among quantum steering, quantum entanglement, energy storage, and extractable work. It is found that within the steerable range, the quantum steering of different qubits has a maximum or minimum value, which corresponds to the energy storage of the battery. Moreover, this maximum or minimum value of quantum steering also corresponds to the maximum value of the extractable work. The minimum of quantum entanglement always coincides with the maximum of parameters like energy storage. Ultimately, the reasons for these results are analyzed by analyzing the purity of the system and discover a relatively general conclusion: when the purity is at its maximum, important parameters such as the energy storage of the battery are also at their maximum.
Abstract The advantage of quantum batteries is that quantum resources can be utilized to enhance charging efficiency. The known available quantum resources are quantum entanglement and quantum coherence. In this study, quantum steering is introduced as a new quantum resource into batteries for the first time. By considering two models, namely the Field‐quantum battery and the Cavity–Heisenberg quantum battery, the relationship is analyzed among quantum steering, quantum entanglement, energy storage, and extractable work. It is found that within the steerable range, the quantum steering of different qubits has a maximum or minimum value, which corresponds to the energy storage of the battery. Moreover, this maximum or minimum value of quantum steering also corresponds to the maximum value of the extractable work. The minimum of quantum entanglement always coincides with the maximum of parameters like energy storage. Ultimately, the reasons for these results are analyzed by analyzing the purity of the system and discover a relatively general conclusion: when the purity is at its maximum, important parameters such as the energy storage of the battery are also at their maximum.
ABSTRACT We investigate the relationship between quantum battery capacity and quantum resources in a two‐qubit system consisting of mutually coupled battery and charger subsystems. We find that the battery capacity decreases monotonically with the quantum entanglement, steering, Bell nonlocality and coherence, and peaks when these four quantum resources vanish. Moreover, we reveal the capacity gap between the total system capacity and the sum of the battery and charger spin capacities, which is the residual battery capacity, and establish its positive correlation with entanglement. Furthermore, unlike the first four resources, although the battery capacity decreases monotonically with quantum imaginarity, its disappearance under system detuning does not guarantee a peak capacity, and this effect becomes more pronounced as the detuning increases. In contrast to the first five resources, the quantum state texture shows a positive correlation with battery capacity, but a negative correlation with entanglement, steering, Bell nonlocality, coherence, imaginarity, and residual battery capacity. These monotonic relationships are independent of the choice of system parameters. Our findings reveal the relationship between quantum battery capacity and quantum resources during the dynamic evolution of a quantum battery system, and advances the theory of quantum batteries and the development of quantum energy storage systems.
We investigate the relationship between quantum battery capacity and quantum resources in a two-qubit system consisting of mutually coupled battery and charger subsystems. We find that the battery capacity decreases monotonically with the quantum entanglement, steering, Bell nonlocality and coherence, and peaks when these four quantum resources vanish. Moreover, we reveal the capacity gap between the total system capacity and the sum of the battery and charger spin capacities, which is the residual battery capacity, and establish its positive correlation with entanglement. Furthermore, unlike the first four resources, although the battery capacity decreases monotonically with quantum imaginarity, its disappearance under system detuning does not guarantee a peak capacity, and this effect becomes more pronounced as the detuning increases. In contrast to the first five resources, the quantum state texture shows a positive correlation with battery capacity, but a negative correlation with entanglement, steering, Bell nonlocality, coherence, imaginarity, and residual battery capacity. These monotonic relationships are independent of the choice of system parameters. Our findings reveal the relationship between quantum battery capacity and quantum resources during the dynamic evolution of a quantum battery system, and advances the theory of quantum batteries and the development of quantum energy storage systems.
We discuss how to enhance the charging performance of quantum battery via two entangled auxiliary qubits. The results demonstrate that the quantum battery achieves optimal charging performance when the two auxiliary qubits are in the initial state of maximum entanglement. On this basis, we further discuss the impacts of dissipation and driving strength of the classical field on the charging performance of the quantum battery. It is shown that the quantum battery exhibits higher energy when the dissipation is low. Weak driving strength plays a regulatory role in the energy storage of the quantum battery. Additionally, we compare the performance differences of the quantum battery when the two entangled auxiliary qubits are in different initial states. Our research findings reveal the advantages of entangled auxiliary qubits in enhancing the charging performance of the quantum battery.
Abstract Finding a quantum battery model that demonstrates a quantum advantage while remaining feasible for experimental production is a considerable challenge. Here, a superconducting quantum battery (SQB) model that exhibits such an advantage is introduced. The model consists of two coupled superconducting qubits that interact during the unitary charging process while remaining in equilibrium with a thermal reservoir. First, the model is described, evidence of the quantum advantage is provided, and then the fabrication process of the battery is discussed using superconducting qubits. Analytical expressions for the ergotropy, instantaneous power, and capacity of the SQB, as well as their connection to quantum coherence are derived. It is demonstrated that leveraging the collective effects of Josephson energies and the coupling energy between qubits allows for optimization, resulting in improved energy redistribution and a significant enhancement in charging efficiency. This work highlights the complexities of tuning system parameters, which increase the potential for work extraction from the SQB, providing a deeper understanding of the charging mechanisms involved. These findings can be applied to superconducting quantum circuit battery architectures, underscoring the feasibility of efficient energy storage in these systems. These results pave the way for proposals of new superconducting devices, emphasizing their potential for efficient energy storage.
Abstract This study explores the energy storage dynamics of a quantum battery (QB) modeled using a dipolar spin system with Dzyaloshinskii–Moriya (DM) interaction. We examine the performance of this system in terms of ergotropy, instantaneous power, capacity, and quantum coherence using a two-qubit model. By solving the system’s time evolution under cyclic unitary processes, we analyze how external parameters such as temperature, magnetic field, and DM interaction influence the charging behavior and quantum resources of the battery. The findings demonstrate that quantum coherence and DM interaction significantly enhance the energy storage efficiency and power output of the quantum battery, offering promising strategies for designing high-performance quantum energy storage devices. Furthermore, we investigate the performance of quantum battery under the influence of a common dephasing environment, which limits the long-term work-extraction capability of dipolar quantum batteries.
We consider a central-spin battery where Nb central spins serve as battery cells and Nc bath spins serve as charging units. It is shown that the energy stored in the battery that can be extractable is quantified by the ergotropy, and that battery-charger entanglement is quantified via the Von Neumann entropy. By using an exact approach to a one-cell and two-cell battery, our analytical results suggest that, during the charging process, the extractable work slowly increases before the battery-charger entanglement reaches its maximum and then it will rapidly increase when the entanglement begins to decrease. In particular, we rigorously show that there is an inverse relationship between the extractable work and the entanglement at the end of the charging process. Moreover, we investigate different approaches to realize optimal work extraction without wasted energy. Among them a central-spin battery with an unpolarized Dicke state as the charger possesses a universal charging time $\ensuremath{\propto}1/{N}_{c}$, large extractable work and Nc-improvement of charging power compared with the battery in the Tavis-Cummings limit. The above-mentioned results have also been numerically verified in multicell batteries. Our results pave the way to improve extractable work storage in the central-spin battery and highlight a competitive relation between the extractable work and the battery-charger entanglement.