This study investigates the performance of extended nonreciprocal quantum batteries (QBs), as well as its advantages in energy storage and energy transfer compared to reciprocal charging and the original nonreciprocal batteries. After analyzing the detuning between the charging system and the external pump, we discover that resonance is a key factor in maintaining high-energy batteries and high charging power; furthermore, the detuning of the charger or battery determines the stability of the charging process for different structures. Research on steady-state energy storage in batteries revealed that single-threaded or multi-threaded charging can achieve nearly infinite energy storage in weakly localized environments, thereby demonstrating the significant energy advantages of extended nonreciprocal quantum batteries. Finally, by considering the energy distribution within the charging system, we observe that nonreciprocal charging offers energy transfer advantages unmatched by reciprocal charging; the former achieves a comprehensive balance between charging cost and energy storage capacity that the latter cannot match. As a novel and superior charging protocol, our findings are expected to provide a potent reference for the promotion and practical implementation of nonreciprocal charging.
This study investigates the performance of extended nonreciprocal quantum batteries (QBs), as well as its advantages in energy storage and energy transfer compared to reciprocal charging and the original nonreciprocal batteries. After analyzing the detuning between the charging system and the external pump, we discover that resonance is a key factor in maintaining high-energy batteries and high charging power; furthermore, the detuning of the charger or battery determines the stability of the charging process for different structures. Research on steady-state energy storage in batteries revealed that single-threaded or multi-threaded charging can achieve nearly infinite energy storage in weakly localized environments, thereby demonstrating the significant energy advantages of extended nonreciprocal quantum batteries. Finally, by considering the energy distribution within the charging system, we observe that nonreciprocal charging offers energy transfer advantages unmatched by reciprocal charging; the former achieves a comprehensive balance between charging cost and energy storage capacity that the latter cannot match. As a novel and superior charging protocol, our findings are expected to provide a potent reference for the promotion and practical implementation of nonreciprocal charging.
This thesis compares the charging capacity of a reciprocal and a nonreciprocal quantum battery in the steady state. The model consists of two qubits functioning as a charger and a battery, where the charger is subjected to a linear driving field and the two qubits are linked via a coherent coupling. Both subsystems are coupled to separate dissipative environments, with an additional joint environment introduced in the nonreciprocal case. It is shown that the qubit quantum battery is limited to a maximum charging level of 50\% in both the reciprocal and nonreciprocal configurations. Surprisingly, the nonreciprocal battery exhibits zero population under the analytically obtained conditions where energy backflow from the battery to the charger is entirely suppressed. Instead, a nonreciprocal advantage emerges exclusively in the weak coupling regime. In this domain, the optimal system configuration requires nearly symmetrical dissipation, favoring a slightly stronger coupling of the charger to the shared environment. Finally, the battery's performance relative to the charger is maximized under a weak drive when the coherent coupling is deactivated and the charger dissipates substantially more energy into the shared environment than the battery.
Nonreciprocal quantum batteries harness reservoir engineering for controlled energy transfer, heralding a paradigm shift for quantum energy storage. A prior study utilizing the Metelmann-Clerk formalism reported a fourfold enhancement in nonreciprocal energy accumulation over reciprocal counterparts. This fourfold enhancement, however, appears to stem from a Lindblad master equation that exhibits fundamental inconsistencies, which may systematically understate the actual nonreciprocal advantage. Our approach is rooted in the rigorously established cascaded open quantum systems formalism, which ensures both mathematical consistency and physical fidelity. Remarkably, we surpass the previously reported fourfold benchmark, attaining a regime-independent sixteenfold steady-state nonreciprocal energy advantage over reciprocal systems. We further uncover a dissipation-dependent battery-to-charger efficiency, fourfold under symmetric damping, surpassing this benchmark when the battery is less dissipative, and lower otherwise. This work establishes the cascaded formalism as a mathematically rigorous and experimentally viable foundation for high-performance quantum energy storage.
Nonreciprocal quantum batteries offer superior charging performance compared to reciprocal quantum batteries. We consider a charger-battery system comprising two optical cavities that interact independently with a third auxiliary cavity. We show that the nonzero dissipation of the auxiliary cavity induces a nonreciprocal exchange of excitations among the charger-battery system. Therefore, by engineering the loss in the auxiliary cavity, we induce a directional energy flow that enhances the charging efficiency. Using numerical and analytical calculations, we show that the steady-state energy stored in the battery significantly exceeds that in the charger. We compare our results with those of the reciprocal cases and demonstrate that our nonreciprocal quantum battery model exhibits a significant charging advantage. We believe that our proposed scheme represents a step forward in cavity-loss engineering, making it a viable approach for nonreciprocal quantum batteries with existing experimental techniques.
Quantum batteries (QBs), harnessing quantum systems to transfer and store energy, have garnered substantial attention recently, enabling potentials in enhanced charging capacity, increased charging power, and device miniaturization. However, constrained by the weak interaction between the quantum nodes, the implementations of QB networks exhibit limited charging performance. In this work, we propose an efficient approach to improving charging in multibattery systems by capitalizing on nonreciprocity. By constructing non-Hermitian Aharonov-Bohm triangles to establish unidirectional energy transfer in both cascaded and parallel configurations, we can achieve a significant enhancement of the stored energy in QBs under weak interaction. Remarkably, the nonreciprocal cascaded setups display an exponentially increasing gain in the battery energy as the charging distance lengthens compared to the reciprocal counterparts. Furthermore, we demonstrate that nonreciprocity can also lead to the same enhancement in the charging power of QBs, accelerating the charging processes. Our findings provide a practical pathway for enhancing the charging performance of QBs and exhibit the potentials for constructing efficient QB networks.
Nonreciprocity, arising from the breaking of time-reversal symmetry, has become a fundamental tool in diverse quantum technology applications. It enables directional flow of signals and efficient noise suppression, constituting a key element in the architecture of current quantum information and computing systems. Here we explore its potential in optimizing the charging dynamics of a quantum battery. By introducing nonreciprocity through reservoir engineering during the charging process, we induce a directed energy flow from the quantum charger to the battery, resulting in a substantial increase in energy accumulation. Despite local dissipation, the nonreciprocal approach demonstrates a fourfold increase in battery energy compared to conventional charger-battery systems. This effect is observed in the stationary limit and remains applicable even in overdamped coupling regimes, eliminating the need for precise temporal control over evolution parameters. Our result can be extended to a chiral network of quantum nodes, serving as a multicell quantum battery system to enhance storage capacity. The proposed approach is straightforward to implement using current state-of-the-art quantum circuits, both in photonics and superconducting quantum systems. In a broader context, the concept of nonreciprocal charging has significant implications for sensing, energy capture, and storage technologies or studying quantum thermodynamics.
We propose a scheme to achieve a nonreciprocal quantum battery (QB) in the non-Hermitian (NH) system, which can overcome the intrinsic dissipation and reverse flow constraints. The design is based on a charger and a battery, which are coherently coupled and jointly interact with a bad cavity. By introducing the auxiliary bad cavity and exploiting the nonreciprocal condition, this model can harness the environmental dissipation to suppress the reverse energy transfer. Under resonant conditions, we have achieved a four ratio of the battery energy to the charger energy; in contrast, this ratio is significantly reduced under large detuning. Through damping optimization, high efficiency of the short-time charging power is attained. In comparison to the fully nonreciprocal scheme, the QB operating at the exceptional point (EP) exhibits greater resilience to parameter fluctuations. These findings highlight the potential of NH quantum engineering for advancing QB technology, particularly in regimes involving directional energy transfer, controlled dissipation, and entropy management in open quantum systems.