麻豆淫院

Quantum batteries (QBs) are energy storage devices that could serve as an alternative to classical batteries, potentially charging faster and enabling the extraction of more energy. In contrast with existing batteries, these batteries leverage effects rooted in quantum mechanics, such as entanglement and superposition.

Despite their promise, QBs have not yet reached optimal performances, partly because they are prone to decoherence simultaneously. This is a loss of coherence (i.e., the ability of quantum systems to exist in a superposition of multiple states), prompted by interactions between a system and its surrounding environment.

Decoherence causes QBs to self-discharge, or in other words, to spontaneously start releasing the energy they are storing. This self-discharging process has so far prevented the batteries' practical application.

Researchers at Hubei University, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, and Lanzhou University have recently introduced a new scheme that could mitigate self-discharging in quantum batteries. Their paper, in 麻豆淫院ical Review Letters, introduces a new QB design in which a defect in diamond, specifically the nitrogen-vacancy center, serves as the medium to store energy.

"A quantum-technology revolution is underway, which uses quantum resources to overcome various performance limitations of devices set by classical physics," Jun-Hong An, co-senior author of the paper, told 麻豆淫院.

"As quantum technologies develop and become more widely used, people are getting better at detecting, processing, and securing information. In addition to 'information,' quantum technologies are increasingly focusing on the topic of 'energy.' This has led to the emergence of the field of quantum thermodynamics."

Past theoretical studies suggest that QBs could have notable advantages over their classical counterparts. Most notably, they could exhibit stronger charging power, a higher charging capacity and larger extractable work, enabled by quantum effects and specific atomic-scale bottom-up fabrication techniques.

"The practical realization and application of QBs face two major challenges," said An. "One is the degraded charging efficiency due to decoherence during the charging process. The other is the spontaneous energy loss, called self-discharging, caused by decoherence during the storage process. Therefore, how to overcome these challenges is a key issue in the field of QBs."

In an earlier paper published in 2024, the researchers tried to overcome the first common shortcoming of QBs, namely the decline in their charging efficiency, using a newly developed anti-aging and wireless-charging protocol. Building on this earlier paper, they now set out to also mitigate the self-discharging processes observed in many previously developed QBs.

"Several schemes have been proposed to suppress the self-discharging of QBs, but they require a quantum charger," explained An. "However, the charger-battery entanglement would decrease the ergotropy of QBs. In contrast to those schemes, we propose a paradigm-shifting solution: a QB based on nitrogen-vacancy (NV) center of diamond that intrinsically suppresses self-discharging without charger intervention. The electronic spin of the NV center is taken as the QB."

Interestingly, the researchers observed that the coherent energy stored by their QB (i.e., coherent ergotropy) decayed more slowly than the incoherent energy during the storage process. Inspired by this observation, they identified a mechanism that could enhance the robustness of their battery against self-discharging by increasing the ratio of coherent ergotropy to the total ergotropy stored by the battery.

"The main advantage of our QB scheme in the NV center is that the unique hyperfine interaction between the electron and the ¹⁴N nucleus, which is absent in other platforms, permits us to coherently optimize this ratio," said An. "This is the irreplaceable feature of our QB scheme in the NV center. This irreplaceability endows us with the ability to mitigate the self-discharging on one hand, and to maximize the extractable work on the other."

In initial tests, the QB introduced by An and his colleagues was found to be less prone to self-discharging prompted by decoherence than QBs they created in the past. Notably, their paper also introduces a promising experimental platform for extracting work in open quantum systems, which could be used by other teams in future studies.

"As part of our study, we integrated a solid-state platform with the rapidly developing field of quantum thermodynamics," said An. "Therefore, by unifying theoretical insight with an experimentally feasible NV-center system, we provide a definitive step toward realizing quantum-enhanced energy devices. It is expected that, in close alignment with , our work would hopefully prompt the development of NV-center quantum thermodynamics."

The recent work by this team of researchers opens new possibilities for the development of more resilient QBs that could be reliably deployed in real-world settings. As part of their next studies, An and his colleagues plan to improve their battery's scalability and test its performance in further experiments.

"More specifically, we plan to develop a many-body QB model that works in a self-discharging-immune way," added An. "This could enable us to efficiently harness the advantages of quantum entanglement to enhance the charging power, charging capacity, and extractable work in our self-discharging mitigated QB."

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