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.
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.
We discuss a one-dimensional coupled qubit-array quantum battery model under Born-Karman boundary conditions and investigate both the charging and discharging processes. Applying the stored energy, charging power, and ergotropy as the essential physical indicators of quantum battery, it is observed that minimizing the hopping interaction between the nearest-neighbor qubits in the qubit-array and increasing the number of qubits during battery setup are crucial. Additionally, we employ a classical driving field to optimize battery performance and explore the optimal quantum battery performance by adjusting the driving strength of the classical field. Finally, we have discovered that the initial energy in the charger no longer needs to be higher than the energy in the battery in our protocol, the charger will continue to supply energy to the battery even when there is limited initial available energy in the charger. And the conventional approach of preparing the battery's initial state in its ground state, as observed in previous studies, may not necessarily be the optimal choice. By introducing a strong classical driving field, it is possible to enhance energy storage by allowing for an initial presence of some energy within the battery.
We establish a general implementation-independent approach to assess the potential advantage of using highly entangled quantum states between the initial and final states of the charging protocol to enhance the maximum charging power of quantum batteries. It is shown that the impact of entanglement on power can be separated from both the global quantum speed limit associated with an optimal choice of driving Hamiltonian and the energy gap of the batteries. We then demonstrate that the quantum state advantage of battery charging, defined as the power obtainable for given quantum speed limit and battery energy gap, is not an entanglement monotone. A striking example we provide is that, counterintuitively, independent thermalization of the local batteries, completely destroying any entanglement, can lead to larger charging power than that of the initial maximally entangled state. Highly entangled states can thus also be potentially disadvantageous when compared to product states. We also demonstrate that taking the considerable effort of producing highly entangled states, such as W or k-locally entangled states, is not sufficient to obtain quantum-enhanced scaling behavior with the number of battery cells. Finally, we perform an explicit computation for a Sachdev–Ye–Kitaev battery charger to demonstrate that the quantum state advantage allows the instantaneous power to exceed its classical bound.
Although entanglement is considered as a crucial resource for quantum information processing, it is still unknown whether the presence of quantum entanglement in the working medium can enhance the charging performance of a quantum battery (QB). Here, we address this problem by considering a QB with working medium consisted of an entangled coupled-cavity array. We show that the optimal charging performance of the QB is achieved in the two-cavity case when cavities are initially in a maximum entangled state without cavity couplings. We then extend our discussion to multicavity case. It is demonstrated that the charging power of the QB under an entangled coupled-cavity array can be further enhanced by increasing the number of cavities. Our findings reveal the advantage of an entangled working medium in enhancing the charging performance of a QB, and therefore, contribute to the experimental realization of quantum batteries with excellent performance.
Efficient Charging of the Quantum Battery Based on the Driven Heisenberg J1−J2J1−J2 Model
Abstract The use of an optical cavity to embed an ensemble of two‐level system, holds promise for enhancing the charging power of a quantum battery. In this study, an ultrafast charging quantum battery based on the driven Heisenberg model is proposed. Various charging performance metrics are analyzed, including energy storage, average charging power, and energy quantum fluctuation. Additionally, the dependence of the maximum energy storage and the maximum charging power on the number of atoms is also discussed. Notably, a quantum advantage is obtained in the maximum charging power, which can be approximately described by the scaling relation . When the coupling between atoms and the cavity is not strong, it is further showed that such a quantum battery can reach the quantum advantage by optimizing parameters under the collective charging scheme. Finally, regarding the external environment as a resource for auxiliary charging, a more stable charging process can be achieved for the quantum battery.
This paper discusses the evolving dynamics of a quantum battery (QB) model consisting of two qubits interacting with a cavity field via multi-photon transitions. Employing the Lindblad master equation to account for dissipative effects, we investigated energy charging, charging power, ergotropy, and energy fluctuations to ascertain optimal conditions for efficient energy storage and extraction. Our results elucidate that lower photon numbers and moderate coherent state result in higher energy peaks and more stable storage. The charging power underscores the significance of maximizing initial energy transfer rates while mitigating rapid power decay. Ergotropy, representing the maximum extractable energy, is highly sensitive to dissipation rates, with elevated photon numbers enhancing charging efficiency but reducing stability. Energy fluctuation reveals that systems with higher photon numbers exhibit greater instability, emphasizing the necessity for controlling dissipation to preserve energy stability.
This study investigates the dynamical behaviour of a two-cell (two-atom) quantum battery driven by a two-mode charging field. We explore the influence of varying interaction strengths on the system?s performance. This includes increasing the coupling between cells and charging fields, and cells themselves through a dipole interaction and Ising interaction along the z-axis. Additionally, the impact of environmental effects is examined by incorporating decay terms for both the charging fields and the cells. Our analysis focuses on key performance metrics such as stored energy, average power, ergotropy, energy fluctuations, and quantum speed limit time. The results reveal that the environment negatively impacts stored energy, power, and ergotropy, but leads to higher speed limits. Enhanced coupling between the charging fields and the cells improves the studied correlations, promoting efficient energy transfer and decreasing speed limit time. Increasing the coupling between the cells, either via the dipole or Ising interaction, generally exhibits a similar effect. This involves a decrease in maximum achievable energy storage, accompanied by the emergence of more erratic energy fluctuations.