Efficient operation of quantum batteries requires not only fast energy transfer but also the ability to halt the charging process to prevent reverse flow. Existing approaches typically rely on direct control of the charger-battery interaction, which can be experimentally demanding. Here we propose a modulator-assisted quantum battery protocol that enables indirect control of energy transfer while keeping the interaction always on. By applying repeated local unitary operations to an auxiliary modulator qubit, we exploit a Zeno-like mechanism to dynamically reshape the effective Hamiltonian and switch the charger-battery coupling on and off. We demonstrate this mechanism in a minimal three-body model and show that it remains effective beyond the ideal fast-control limit. We further extend the protocol to a collective many-body architecture, where it preserves the characteristic enhancement of charging power, scaling as N 3 / 2 with the number of battery units. We also discuss a possible implementation in an NV- 13 C spin platform. Our results establish modulator-assisted Zeno control as a scalable route to regulating energy transfer in quantum batteries.
Efficient operation of quantum batteries requires not only fast energy transfer but also the ability to halt the charging process to prevent reverse flow. Existing approaches typically rely on direct control of the charger-battery interaction, which can be experimentally demanding. Here we propose a modulator-assisted quantum battery protocol that enables indirect control of energy transfer while keeping the interaction always on. By applying repeated local unitary operations to an auxiliary modulator qubit, we exploit a Zeno-like mechanism to dynamically reshape the effective Hamiltonian and switch the charger-battery coupling on and off. We demonstrate this mechanism in a minimal three-body model and show that it remains effective beyond the ideal fast-control limit. We further extend the protocol to a collective many-body architecture, where it preserves the characteristic enhancement of charging power, scaling as N 3 / 2 with the number of battery units. We also discuss a possible implementation in an NV- 13 C spin platform. Our results establish modulator-assisted Zeno control as a scalable route to regulating energy transfer in 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.
Arbitrary energy transfer is only feasible in nondissipative charger-battery systems; in realistic processes, however, energy dissipation prevents this. In this work, we introduce a novel charging technique in which the coherent charger-battery interaction is replaced by a dissipative interaction via an engineered reservoir. We demonstrate that exploiting the collective effects of the engineered reservoir allows for additional optimization, giving rise to an optimal redistribution of energy. This not only significantly enhances the efficiency of the charging process but also remarkably enables the quantum battery to accumulate unlimited energy---limited only by the natural energy scale of the device. This phenomenon cannot occur in conventional charger-battery schemes. The article unveils the intricacies of built-in detuning within the context of a shared environment, offering a deeper understanding of the charging mechanisms involved. These findings apply naturally to quantum circuit battery architectures, suggesting the feasibility of efficient energy storage in these systems. The superoptimal charging mechanism offers a practical avenue for boosting the capacity of the battery through charger-battery configurations.
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.
Quantum battery works as a micro- or nanodevice to store and redistribute energy at the quantum level. Here we propose a spin-charger protocol, in which the battery cells are charged by a finite number of spins through a general Heisenberg XY interaction. Under the isotropic interaction, the spin-charger protocol is endowed with a higher capacity in terms of the maximum stored energy than the conventional protocols, where the battery is charged by a continuous-variable system, e.g., a cavity mode. By tuning the charger size, a tradeoff between the maximum stored energy and the average charging power is found in comparison to the cavity-charger protocol in the Tavis-Cummings model. Quantum advantage of our protocol is manifested by the scaling behavior of the optimal average power with respect to the battery size, in comparing the collective charging scheme to its parallel counterpart. We also discuss the detrimental effect on the charging performance from the anisotropic interaction between the battery and the charger, the nonideal initial states for both of them, and the crosstalk among the charger spins. A strong charger-charger interaction can be used to decouple the battery and the charger. Our findings about the advantages of the spin-charger protocol over the conventional cavity-charger protocols, including the high capacity of energy storage and the superior power law in the collective charging, provide an insight to exploit an efficient quantum battery based on the spin-spin-environment model.
Quantum batteries provide a platform for investigating energy storage and extraction in quantum many-body systems. Here, we study a charging protocol in which battery and chargoid roles are assigned to different Hamiltonian components of a standalone many-body spin system. By externally controlling the contribution of the intrinsic battery Hamiltonian during charging, we reveal a tunable competition between intrinsic and charging dynamics. We find that suppressing the intrinsic battery contribution can substantially enhance both the maximum stored energy and charging power, with the magnitude of the enhancement determined by the interaction structure and range. We further investigate the protocol in a Markovian open-system setting that incorporates energy relaxation and pure dephasing. While environmental effects generally degrade charging performance, they can instead enhance energy-storage and energy-extraction dynamics in certain interacting systems. The enhancement associated with the controlled suppression of the intrinsic battery dynamics remains robust in the presence of environmental coupling.