We investigate the charging process of open quantum battery in the weak system-environment coupling regime. A method to improve the performance of open quantum battery in a reservoir environment, which described by a band-gap environment model or a two-Lorentzian environment model, is proposed by manipulating the spectral density of environment. We find that the optimal quantum battery, characterized by fast charging time and large ergotropy, in the band-gap environment can be obtained by increasing the weights of two Lorentzians and the spectral width of the second Lorentzian, which is in sharp contrast to the quantum battery in two-Lorentzian environment. Then we extend our discussion to multiple coupled reservoir environments, which are composed of N coupled dissipative cavities. We show that, the performance of quantum battery can be enhanced by increasing the coupling strength between the nearest-neighbor environments and decreasing the size of the environments. In particular, to fully charge and extract the total stored energy as work for quantum battery can be achieved by manipulating the coupling strength between the nearest-neighbor environments. Our results provide a practical approach for the realization of the optimal quantum batteries in future experiments.
We investigate the charging process of open quantum battery in the weak system-environment coupling regime. A method to improve the performance of open quantum battery in a reservoir environment, which described by a band-gap environment model or a two-Lorentzian environment model, is proposed by manipulating the spectral density of environment. We find that the optimal quantum battery, characterized by fast charging time and large ergotropy, in the band-gap environment can be obtained by increasing the weights of two Lorentzians and the spectral width of the second Lorentzian, which is in sharp contrast to the quantum battery in two-Lorentzian environment. Then we extend our discussion to multiple coupled reservoir environments, which are composed of N coupled dissipative cavities. We show that, the performance of quantum battery can be enhanced by increasing the coupling strength between the nearest-neighbor environments and decreasing the size of the environments. In particular, to fully charge and extract the total stored energy as work for quantum battery can be achieved by manipulating the coupling strength between the nearest-neighbor environments. Our results provide a practical approach for the realization of the optimal quantum batteries in future experiments.
Abstract We investigate the stabilization mechanism of open quantum batteries driven by a classical field in the weak or strong system-reservoir coupling regime. A protocol to improve the steady-state energy storage performance is proposed by engineering the spectral density of a band-gap environment which is described as the superposition of two inhomogeneous Lorentzian spectrums with different weights. We find out that the interplay between the battery-environment-bound state and the reservoir memory effect plays a crucial role in the stabilization performance against energy dissipation. The formation of the bound state and the non-Markovian effect will be strengthened by adjusting the weights of the environment spectral density. In the charging process, the classical field contributes to enhancing the steady ergotropy. Moreover, the manipulation of the spectrum weights results in the speedup scheme of carrying out the energy storage due to the existence of bound states. In the self-discharging process, increasing the spectral weight allows the battery to maintain a higher steady ergotropy. These results provide a practical approach to achieving optimal quantum batteries with better stabilization performance.
In the process of using quantum resources to improve the performance of quantum battery devices, device performance is highly restricted by decoherence due to the influence of the external environment. In particular, the fact that such devices are subject to complex environmental influences in real scenarios should be taken into account. Here, we investigate the performance (i.e., the internal energy, charging power, and ergotropy) of a quantum battery in a double-layer environment, where the first-layer environment is a single-mode cavity and the second-layer environment is a single reservoir. We are surprised to find that the memory effect of the reservoir does not affect the charging performance of a quantum battery; in sharp contrast, the reduction in the coupling between the quantum battery and the first-layer environment can improve the charging performance of a quantum battery. We then extend our discussion to the case where the second-layer environment consists of multiple reservoirs, each consisting of a single-mode cavity dissipated to the Markovian reservoir. It is shown that the charging performance of the quantum battery can be enhanced by increasing the number of cavities in the second-layer environment and the coupling strength between the first-layer environment and the second-layer environment. Our results may be helpful for realizing optimal charging performance of quantum batteries in a complex environment.
How to improve charging processes and suppress self-discharging processes has always been one of the key issues to achieve quantum batteries with high performance. Although a quantum battery is inevitably influenced by composite environments, this situation is still little understood, particularly regarding the influence of the memory effect of the composite environments and the coupling between composite environments. In this work, we investigate the effects of the composite environments, composed of two identical parts each containing a single cavity mode decaying to a reservoir, on the charging and self-discharging processes of a quantum battery. We show that increasing the two-mode coupling can effectively enhance the charging performance (i.e., the stored energy, the charging power, ergotropy) and restrain the self-discharging process (i.e., suppressing the process of dissipating the energy). However, different from the effect of two-mode coupling, we reveal that the memory effect of the reservoir in this composite environment is unfavorable to the charging process of the quantum battery, which is in sharp contrast to previous studies where the memory effect can significantly improve the charging performance of a quantum battery. Our results may benefit to the realization of quantum batteries with high performance under the actual complex environmental noise.
Abstract The charging process of a quantum battery (i.e., a two‐level system) is studied in two scenarios, that is, a quantum battery and a charger are coupled to the common reservoir environments or coupled to their respective independent environments. In the common reservoir scenario, it is shown that the optimal charging process can be realized by increasing the number of environments and setting the same coupling strength between battery‐reservoirs and charger‐reservoirs. In the independent reservoir scenario, however, it is shown that decreasing either the number of reservoir environments or the coupling strength would enhance the charging performance. These results demonstrate that the charging performance of quantum batteries can be significantly improved by constructing common environments. This may be of help to the realization of the quantum battery with optimal charging performance in multiple environments.
Quantum batteries, as highly efficient energy storage devices, have garnered significant research interest. A key challenge in their development is to maximize the extractable energy (ergotropy) when operating within a finite-temperature reservoir. To address this, we applied quantum feedback control to the charger and investigated the effects of fermionic and bosonic thermal reservoirs on the performance of quantum batteries, including stored energy, ergotropy, and charging efficiency, in an open environment. Our findings reveal that, regardless of the type of thermal reservoir, the system exhibits optimal charging parameters. In particular, in a fermionic thermal reservoir, increasing the environmental temperature enhances battery performance, enabling stable and efficient charging. In contrast, within a bosonic thermal reservoir, higher temperatures hinder energy storage and extraction, significantly reducing charging efficiency. Additionally, we explored the impact of battery size and found that, under a fermionic reservoir, increasing the battery size appropriately can further improve performance.
Abstract Reservoir engineering has been widely used in various quantum technologies. Based on a cavity-QED (quantum electrodynamics) model, we propose a potentially practical scheme using squeezed-vacuum reservoir engineering to optimize the performance of a quantum battery (QB) located inside a cavity driven by a broadband squeezed laser, which acts as a squeezed-vacuum reservoir. Using the reduced master equation of the QB obtained via the adiabatic elimination method, we focus on the QB’s charging dynamics under tunable squeezed reservoirs governed by parametrically controlled squeezing parameters, which dictate the efficiency of energy transfer and the extractable work (ergotropy) of the QB. We show that increasing the squeezing strength improves the charging rate and enables rapid energy transfer, whereas the steady-state energy of the QB saturates at specific values of the squeezing parameter. Notably, the ergotropy of the QB reaches its maximum at a critical squeezing strength and does not scale monotonically with the squeezing strength. This nonmonotonic behavior underscores the existence of optimal parameter regimes, through which the performance of the QB can be significantly enhanced.