Abstract The storage and transfer of energy through quantum batteries are key elements in quantum networks. Here, we propose a charger design based on transitionless quantum driving (TQD), which allows for inherent control over the battery charging time, with the speed of charging coming at the cost of the internal energy available to implement the dynamics. Moreover, the TQD-based charger is also shown to be locally stable, which means that the charger can be disconnected from the quantum battery (QB) at any time after the energy transfer to the QB, with no full energy backflow to the charger. This provides a highly charged QB in an always-on asymptotic regime. We illustrate the robustness of the QB charge against time fluctuations and the full control over the evolution time for a feasible TQD-based charger.
Abstract The storage and transfer of energy through quantum batteries are key elements in quantum networks. Here, we propose a charger design based on transitionless quantum driving (TQD), which allows for inherent control over the battery charging time, with the speed of charging coming at the cost of the internal energy available to implement the dynamics. Moreover, the TQD-based charger is also shown to be locally stable, which means that the charger can be disconnected from the quantum battery (QB) at any time after the energy transfer to the QB, with no full energy backflow to the charger. This provides a highly charged QB in an always-on asymptotic regime. We illustrate the robustness of the QB charge against time fluctuations and the full control over the evolution time for a feasible TQD-based charger.
The performance of open quantum batteries (QBs) is severely limited by decoherence due to the interaction with the surrounding environment. So, protecting the charging processes against decoherence is of great importance for realizing QBs. In this work we address this issue by developing a charging process of a qubit-based open QB composed of a qubit-battery and a qubit-charger, where each qubit moves inside an independent cavity reservoir. Our results show that, in both the Markovian and non-Markovian dynamics, the charging characteristics, including the charging energy, efficiency and ergotropy, regularly increase with increasing the speed of charger and battery qubits. Interestingly, when the charger and battery move with higher velocities, the initial energy of the charger is completely transferred to the battery in the Markovian dynamics. In this situation, it is possible to extract the total stored energy as work for a long time. Our findings show that open moving-qubit systems are robust and reliable QBs, thus making them a promising candidate for experimental implementations.
Controlling the charging process of a quantum battery involves strategies to efficiently transfer, store, and retain energy, while mitigating decoherence, energy dissipation, and inefficiencies caused by surrounding interactions. We develop a model to study the charging process of a quantum battery in an open quantum setting, where the battery interacts with a charger and a structured reservoir. To overcome the limitations of static charging protocols, a reinforcement learning (RL) charging strategy is proposed, which utilizes the deep deterministic policy gradient algorithm alongside long short-term memory (LSTM) networks. The LSTM networks enable the RL model to capture temporal correlations driven by non-Markovian dynamics, facilitating a continuous, adaptive charging strategy. The RL protocols consistently outperform conventional fixed heuristic strategies by real-time controlling the driving field amplitude and coupling parameters. By penalizing battery-to-charger backflow in the reward function, the RL-optimized charging strategy promotes efficient unidirectional energy transfer from charger to battery, achieving higher and more stable extractable work. The proposed RL controller would provide a framework for designing efficient charging schemes in broader configurations and multi-cell quantum batteries.
Quantum batteries have emerged as a promising new generation of energy-storage devices for powering quantum technologies. Long-distance charging is particularly attractive because it minimizes interference between the charger and the battery, thereby attracting considerable interest. Here, we propose a topologically protected long-distance charging protocol for quantum batteries based on a pulse-controlled superconducting qubit chain. By dynamically modulating the pulse-mediated couplings, we realize topologically protected energy transfer from the charger to the battery. We show that the charging process is free of energy backflow and remains robust against imperfections in pulse control. Moreover, the energy stored in the battery at the target time is fully extractable, and the protocol remains effective for relatively large system sizes. To further accelerate charging, we optimize the pulse shape and elucidate the underlying physical mechanism. Our pulse-controlled topological quantum battery protocol provides a versatile framework for implementing long-distance topological charging and establishes a theoretical foundation for designing optimal-control strategies to enhance quantum battery performance.
Charger-mediated quantum batteries offer promising opportunities for efficient energy transfer and storage at the quantum level, with potential advantages beyond their classical counterparts. Here, we theoretically demonstrate that nonlinear charger-battery interactions can substantially accelerate the charging of quantum batteries. In the weak-driving regime, sufficiently strong nonlinear coupling can dominate over the effect of dephasing and significantly reduce the charging time. In the strong- and optimal-driving regimes, where the optimal driving strength maximizes the steady-state ergotropy in the linear-coupling regime, nonlinear coupling gives rise to a new optimum in the charging time beyond that of the linear-coupling regime, accompanied by nearly critically damped dynamics. Remarkably, even in the absence of external driving, nonlinear coupling alone can substantially reduce the charging time, providing an alternative route toward fast battery charging. Our results establish nonlinear charger-battery coupling as an effective resource for accelerating quantum-battery charging and broaden the scope of interaction-enabled quantum advantages in energy transfer and storage.
Abstract Quantum batteries are designed to outperform classical batteries by utilizing quantum effects, particularly in charging speed and energy storage efficiency. Quantum batteries based on chargers that interact periodically with an external energy source are analyzed within an open quantum system framework, with battery performance parameters such as charging time and total energy utilized for evaluation. In this paper, the charger and quantum battery are modeled as a quantum harmonic oscillator, and their interaction is governed by the Lindblad master equation. The energy function of the quantum battery is determined by the first momenta obtained by solving a system of coupled first-order linear differential equations formed from the master equation. Based on these results, we investigate the effect of periodic driving on energy charging, energy stability, and decoherence effects in the quantum battery.
We analyze the energy charging of a quantum battery within an open quantum framework, where the interaction between the battery element and an external power source is mediated by an ancilla system acting as a controllable switch. Specifically, we investigate the charging and discharging dynamics of a cavity-based quantum battery coupled to a driven qubit functioning as the charger. To ensure lossless power transfer, we utilize an adiabatic evolution protocol. Furthermore, we implement counterdiabatic driving, achieved by applying an auxiliary control field to the original Hamiltonian, to suppress undesired transitions and realize fast adiabatic dynamics. This scheme significantly accelerates the charging process. We demonstrate that the charging efficiency under adiabatic evolution is enhanced and exhibits stable, non-oscillatory behavior, and we determine the optimal duration for the operation. Finally, we show that counterdiabatic driving minimizes the path length between the initial and final states, inducing the shortest possible evolution distance.