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Physical Review A

Subwavelength quantum battery based on an atomic ring array coupled with an incoherently driven atom

Yuxiang Han, Zhengquan Pan, Hongrong Li

Published Mar 31, 2025• 3 citations
Publisher

Abstract

Many-body quantum batteries composed of $N$ two-level systems benefit from collective effects, demonstrating excellent charging performance. In this paper, we consider a charging scheme where an atomic ring array serves as the quantum battery system, coupled to a central charger atom that is pumped by an incoherent thermal source. Assuming no interactions among the atoms on the ring, the system can be described using the Dicke model, where collective coupling results in a significant initial charging power. When dipole-dipole interactions among the atoms are taken into account, the charging power of the battery decreases due to the introduction of intricate collective dissipation. However, the symmetric coherent interactions facilitate the rapid relaxation of the system's dynamics to the eigenstates, thereby increasing the proportion of useful work within the battery. Moreover, we investigate the impact of the ring size and the detuning of the charger atom on the steady-state ergotropy of the quantum battery. Our findings indicate that, at zero detuning, the system exhibits a larger effective charging ring size. As the magnitude of the detuning increases, the effective charging ring size decreases. By analyzing the radiation properties of the system in its steady state, we also explain why the steady-state ergotropy is higher when the charger atom is positively detuned.

DOI
10.1103/physreva.111.032221

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Many-body quantum batteries composed of NNN two-level systems benefit from collective effects, demonstrating excellent charging performance. In this paper, we consider a charging scheme where an atomic ring array serves as the quantum battery system, coupled to a central charger atom that is pumped by an incoherent thermal source. Assuming no interactions among the atoms on the ring, the system can be described using the Dicke model, where collective coupling results in a significant initial charging power. When dipole-dipole interactions among the atoms are taken into account, the charging power of the battery decreases due to the introduction of intricate collective dissipation. However, the symmetric coherent interactions facilitate the rapid relaxation of the system's dynamics to the eigenstates, thereby increasing the proportion of useful work within the battery. Moreover, we investigate the impact of the ring size and the detuning of the charger atom on the steady-state ergotropy of the quantum battery. Our findings indicate that, at zero detuning, the system exhibits a larger effective charging ring size. As the magnitude of the detuning increases, the effective charging ring size decreases. By analyzing the radiation properties of the system in its steady state, we also explain why the steady-state ergotropy is higher when the charger atom is positively detuned.
ABSTRACT We investigate a quantum battery within an open quantum system, in which a harmonic oscillator acts as the charger and two‐level atoms serve as battery cells. This model accounts for the dissipative effects arising from the coupling between both the charger and battery cells with the environment. By analyzing the time evolution of the battery energy, charging power, ergotropy, and logarithmic negativity, we systematically examine the influence of the number of battery cells and environmental dissipation on battery performance. Our results show that increasing significantly enhances the charging power, exhibiting a collective enhancement effect. Both the atomic number and environmental dissipation strongly affect the ergotropy per atom, but their influences are distinct.
In this dissertation, we investigate the charging and discharging dynamics of a quantum battery composed of a collectively driven ensemble of NNN identical two level systems coupled to a structured electromagnetic environment. The system is described using collective angular momentum operators in the Dicke basis, which provides a compact and physically transparent framework for analyzing collective light-matter interactions. Rather than treating dissipation as an unwanted source of loss, we explicitly use it as a mechanism for energy storage and work extraction. Starting from a coherently driven ensemble coupled to common reservoirs, we derive a master equation in Lindblad form under the Born-Markov and secular approximations. In the dressed-state basis, spontaneous emission induces irreversible transitions that can increase the energy stored in the bare basis. We obtain analytic expressions for the steady state, including the stored energy and the ergotropy, and identify parameter regimes where substantial collective coherence is generated. A central result of this work is the demonstration that, in the extensive regime where the total energy scales linearly with NNN and relative fluctuations vanish, the charging power scales as N2N^2N2. This quadratic enhancement scaling exceeds the N3/2N^{3/2}N3/2 limit previously established for purely Hamiltonian charging protocols of noninteracting Dicke batteries in the same regime. We show that this enhancement is consistent with quantum speed limits for open-system dynamics and originates from collectively enhanced dissipative processes analogous to superradiance. We further analyze the extraction process and show that the charged steady state stores not only energy but a macroscopic collective dipole moment. This coherence enables rapid energy release through either collective spontaneous emission or stimulated emission driven by an external coherent field. In the appropriate large NNN extensive regime, the stored energy can become fully extractable in principle, and the discharging power also exhibits N2N^2N2 scaling. These results establish that dissipative protocols can provide a genuine collective advantage over Hamiltonian schemes in the extensive regime, while also highlighting the interplay between enhanced collective power and the conditions required to achieve high extractable energy.
We study the charging performance of a one-dimensional many-body bosonic quantum battery coupled to a harmonic-oscillator charger. In the weak-coupling regime, we show that the battery--charger dynamics can be accurately described by an effective two-level model, which predicts the resonance condition, optimal charging time, stored work, ergotropy, and charging power. We demonstrate that tuning the charger frequency to the interaction-shifted resonance enables complete energy transfer and maximum extractable work. A many-body charging advantage is observed: increasing the particle number reduces the quantum speed-limit time and enhances the charging power with a characteristic NB\sqrt{N_B}NB​​ scaling. We further introduce a decomposition of the switching cost into resonance-shifting and excitation contributions, allowing us to quantify the energetic overhead associated with the charging process. Owing to the small charging cost relative to the available charger energy, stronger battery--charger couplings can be employed to significantly boost the charging power while maintaining a low excitation cost. Our results highlight the role of resonance engineering and many-body effects in designing fast and efficient quantum batteries, and provide a promising route toward their realization in ultracold-atom platforms.
Abstract Quantum batteries (QBs)—small-scale energy storage devices based on quantum systems—offer the potential for enhanced charging performance through quantum effects such as coherence and collectivity. In this work, we study the collective charging of QBs consisting of N qubits, coupled to a driven qubit charger in a star configuration, with controlled pure dephasing acting on the charger. We investigate how an ‘asymptotic freedom’-like behavior—in which all the energy deposited into the battery can be extracted as work, resulting in the ergotropy-to-energy ratio approaching unity—can emerge in the steady state of the battery. We show that the ergotropy-to-energy ratio increases with the number of qubits and approaches unity asymptotically as 1 − O ( 1 / N ) . In the large- N limit, the emergence of approximate ground-state degeneracy of the collective battery system leads to this asymptotic freedom behavior, despite the battery state remaining mixed. We also discuss the scaling behavior of the charging time of the battery with N .
In this paper, we theoretically investigate the charging dynamics of a closed quantum battery embodied by a four-level atom in a diamond configuration, operating without dissipation. The system is coupled to a single-mode cavity field, which acts as the charger initially prepared in a coherent state, and is simultaneously manipulated by an external classical driving field. By solving the exact system dynamics, we provide a holistic analysis of key performance metrics, including stored energy, ergotropy, energy fluctuations, and von Neumann entropy, as a function of critical system parameters. Our investigation delineates a paramount trade-off; while larger initial charger amplitudes and optimized detunings substantially enhance the stored energy and extractable work, they concurrently amplify fluctuations and entropy, thereby diminishing the battery’s stability and quantum coherence. Crucially, we demonstrate that the coupling to the external drive exhibits a non-monotonic influence, revealing an optimal intermediate regime, specifically at a classical driving strength of λ 2 = 0.5 and detunings δ 1 = δ 3 = 1 ω f , that judiciously balances rapid energy uptake with stable, long-term storage. These results elucidate the complex interplay of coherent control and system parameters, offering critical insights for the rational design of efficient and robust quantum energy storage devices by effectively decoupling charging performance from operational instability.
We examine how a finite many-body system can function as an effective charger for a single-qubit quantum battery, using the Lipkin-Meshkov-Glick model as a paradigmatic setting. As our figure of merit, we consider the battery ergotropy while explicitly resolving the energetic flows across the composite system. In the absence of intra-charger interactions, we show that the generation of non-zero ergotropy is controlled by the competition between collective coupling and spectral mismatch. We further demonstrate that even passive positive-temperature charger states can generate finite battery ergotropy, provided the charger is sufficiently large and sufficiently hot. Intra-charger interactions restructure the charger spectrum and qualitatively modify the available energetic pathways. While they can enhance the amount of energy accessible for charging, they can simultaneously divert energy into internal many-body and battery-charger interaction channels, producing an energetic impedance to direct charger-to-battery transfer. Consequently, battery ergotropy alone is insufficient to characterize an effective many-body charger: the useful work generated and its energetic provenance must be assessed together.