A quantum battery is a temporary energy-storage system. We construct a quantum battery model of an $N$-spin chain with nearest-neighbor hopping interaction and investigate the quantum battery's charging process. We obtain the maximum energy in the quantum battery charged by a coherent cavity driving field or a thermal heat bath. We confirm that for a finite-length spin chain, thermal charging results in a nonzero ergotropy, contradicting a previous result: An incoherent heat source cannot charge a single-spin quantum battery. The nearest-neighbor hopping interaction induces energy-band splitting, enhancing the energy storage and the ergotropy of the quantum battery. We find a critical point in the energy and ergotropy resulting from the ground-state quantum phase transition after which the energy significantly enhances. Finally, we also find that disorder increases the energy of the quantum battery.
A quantum battery is a temporary energy-storage system. We construct a quantum battery model of an N-spin chain with nearest-neighbor hopping interaction and investigate the quantum battery's charging process. We obtain the maximum energy in the quantum battery charged by a coherent cavity driving field or a thermal heat bath. We confirm that for a finite-length spin chain, thermal charging results in a nonzero ergotropy, contradicting a previous result: An incoherent heat source cannot charge a single-spin quantum battery. The nearest-neighbor hopping interaction induces energy-band splitting, enhancing the energy storage and the ergotropy of the quantum battery. We find a critical point in the energy and ergotropy resulting from the ground-state quantum phase transition after which the energy significantly enhances. Finally, we also find that disorder increases the energy of the quantum battery.
Abstract A model of the Heisenberg spin chain quantum battery that is charged by noise is built, and the energy can be extracted. In a phase‐flip noisy environment, it is found that there are sudden changes in steady‐state energy and ergotropy with the variation of the nearest neighbor interaction strength on the plane. These sudden changes are associated with quantum phase transition (QPT), which has been shown through the crossover of the ground state energy level and the first excited state energy level, as well as the order parameters. In a thermal bath, the changes are investigated in steady‐state energy and ergotropy with the variation of the nearest neighbor interaction strength on the plane. The components of Hamiltonian of the battery in the , , and directions are used to explain the steady‐state energy continuity at the QPT points. In addition, the effect of mean occupation number of the thermal bath on the steady‐state energy and ergotropy is also considered. For the general Heisenberg spin chain and ‐qubit batteries, it is proved that the noise can also be used to charge the battery, and the ergotropy is non‐zero.
Quantum batteries, which are energy-storage or state-storage devices that exploit unique quantum effects, are sensitive to environmental noise. Here, we demonstrate that suitably engineered noise can induce a "Zeno-like" stabilization effect of the charging process in a spin-chain quantum battery within the Heisenberg XYZ model. Focusing on a system size N=6, which balances computational cost and storage capacity, we find that the ergotropy-to-energy ratio W(t)/E_B(t) attains a maximum value of about 0.99 at a certain time parameter value. Then, by varying the noise strength in each channel, we find that not only does decoherence merely degrade performance but it may also stabilize stored energy and ergotropy in the high noise strength regime. For instance, the phase-flip channel slows charging and reduces charging power, but its discharging behavior releases energy and ergotropy more slowly, allowing the battery to be used for longer times compared to bit-flip and bit-phase-flip channels. In contrast, the bit-flip channel enables fast charging, but yields low storage and rapid energy release. Remarkably, the bit-phase-flip channel can combine the advantages of both bit-flip and phase-flip channels in the high-noise-strength regime. The bit-phase-flip channel supports accelerated charging together with enhanced storage capacity, while its discharging behavior resembles that of the bit-flip channel with rapid energy release. These results reveal that, under sufficiently strong noise, environmental decoherence induces a Zeno-like stabilization, allowing it to achieve enhanced charging performance and to stabilize stored energy and ergotropy in the spin-chain quantum battery.
Ergotropy serves as a key indicator for assessing the performance of quantum batteries (QBs). Using the Redfield master equation, we investigate ergotropy dynamics in a non-Markovian QB composed of an N-spin chain embedded in a microcavity. Distinct from the Markovian charging process, the thermal charging process exhibits a distinct oscillatory behavior in the extracted ergotropy. We show that these oscillations can be effectively suppressed through coordinated tuning of coherent driving, cavity parameters, and spin-spin couplings. In addition, we analyze the influence of various system and environmental parameters on the time evolution of ergotropy, revealing rich dynamical features. Our results offer insights into the control of energy extraction in QBs and may inform future designs of practical battery architectures.
We investigate the effect of localization on the local charging of quantum batteries (QBs) modeled by disordered spin systems. Two distinct schemes based on the transverse-field random Ising model are considered, with Ising couplings defined on a Chimera graph and on a linear chain with up to next-to-nearest-neighbor interactions. By adopting a low-energy demanding charging process driven by local fields only, we obtain that the maximum extractable energy by unitary processes (ergotropy) is highly enhanced in the ergodic phase in comparison with the many-body localization (MBL) scenario. As we turn off the next-to-nearest-neighbor interactions in the Ising chain, we have the onset of the Anderson localization phase. We then show that the Anderson phase exhibits a hybrid behavior, interpolating between large and small ergotropy as the disorder strength is increased. We also consider the splitting of total ergotropy into its coherent and incoherent contributions. This incoherent part implies in a residual ergotropy that is fully robust against dephasing, which is a typical process leading to the self-discharging of the battery in a real setup. Our results are experimentally feasible in scalable systems, such as in superconducting integrated circuits.
We investigate the performance of a quantum battery exposed to local Markovian and non-Markovian dephasing noises. The battery is initially prepared as the ground state of a one-dimensional transverse XY model with open boundary condition and is charged (discharged) via interactions with local bosonic reservoirs. We show that in the transient regime, the quantum battery (QB) can store energy faster and has a higher maximum extractable work, quantified via ergotropy, when it is affected by local phase-flip or bit-flip Markovian noise compared to the case when there is no noise in the system. In both the charging and discharging processes, we report the enhancement in work output as well as in ergotropy when all the spins are affected by a non-Markovian Ohmic bath in both the transient and the steady-state regimes, thereby showing a counterintuitive advantage of decoherence in the QB. In both Markovian and non-Markovian cases, we identify the system parameters and the corresponding noise models which lead to maximum enhancement of work output and ergotropy. Moreover, we show that the benefit due to noise persists even with the initial state being prepared at a moderate temperature.
Quantum battery, as a novel energy storage device, offers the potential for unprecedented efficiency and performance beyond the capabilities of classical systems, with broad implications for future quantum technologies. Here, we experimentally \RefC{demonstrate quantum charging advantage (QCA)} in a scalable solid-state quantum battery. More specifically, we show how double-excitation Hamiltonians for two-level systems promote scalable QCA \RefB{with standard methods.} We effectively implement the collective evolution of quantum systems with 2 up to 12 battery cells in a superconducting quantum processor, and study the performance of quantum charging compared to its uncorrelated classical counterpart. The model considered is a linear chain of superconducting transmon qubits with only \textit{nearest-neighbor} and \textit{pairwise} interactions, which constitute the simplest model of a multi-cell quantum battery. Our results empirically realize substantial QCA without the necessity of adopting long-range and many-body interactions \RefB{ and showcase the quantum features of the QB charging processes with measurements of non-zero coherent ergotropy, incoherent ergotropy and entanglement,} revealing a promising prospect for further developments of efficient and experimentally feasible protocols for QCA.