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Main Authors: Li, Jinyi, Zheng, Juncheng, Yang, Xue, Hu, Kainan, Zhou, Kanzheng, Zhuang, Junkai, Wang, Hengyan, Ma, Zhihao, Luo, Mingxing, Zheng, Wenqiang
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2604.17518
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author Li, Jinyi
Zheng, Juncheng
Yang, Xue
Hu, Kainan
Zhou, Kanzheng
Zhuang, Junkai
Wang, Hengyan
Ma, Zhihao
Luo, Mingxing
Zheng, Wenqiang
author_facet Li, Jinyi
Zheng, Juncheng
Yang, Xue
Hu, Kainan
Zhou, Kanzheng
Zhuang, Junkai
Wang, Hengyan
Ma, Zhihao
Luo, Mingxing
Zheng, Wenqiang
contents Quantum batteries harness non-classical resources, such as quantum coherence and entanglement, to surpass the performance limits of classical energy-storage devices. Here we realize a room-temperature quantum battery based on a collective atomic spin ensemble in a thermal alkali-metal vapor, containing approximately $10^{12}$ $^{87}$Rb atoms with coherence times exceeding 110 ms. We operationally determine the battery capacity by directly measuring the extremal internal energies accessible under unitary evolution. This tomography-free protocol agrees closely with the conventional state-based definition and verifies the decomposition of capacity into coherent and incoherent contributions. We further show that quantum coherence can substantially enhance the storage capability independently of level populations, and experimentally establish quantitative relations linking battery capacity to von Neumann, Tsallis and linear entropies. By introducing a controlled dephasing channel with a magnetic-field gradient, we observe a monotonic reduction of capacity with coherence loss and track the corresponding evolution of the entropy-capacity relations. Our results identify thermal atomic spin ensembles as a scalable platform for quantum batteries and connect macroscopic quantum energy storage with operational quantum thermodynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2604_17518
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Thermal vapor quantum battery based on collective atomic spins
Li, Jinyi
Zheng, Juncheng
Yang, Xue
Hu, Kainan
Zhou, Kanzheng
Zhuang, Junkai
Wang, Hengyan
Ma, Zhihao
Luo, Mingxing
Zheng, Wenqiang
Quantum Physics
Quantum batteries harness non-classical resources, such as quantum coherence and entanglement, to surpass the performance limits of classical energy-storage devices. Here we realize a room-temperature quantum battery based on a collective atomic spin ensemble in a thermal alkali-metal vapor, containing approximately $10^{12}$ $^{87}$Rb atoms with coherence times exceeding 110 ms. We operationally determine the battery capacity by directly measuring the extremal internal energies accessible under unitary evolution. This tomography-free protocol agrees closely with the conventional state-based definition and verifies the decomposition of capacity into coherent and incoherent contributions. We further show that quantum coherence can substantially enhance the storage capability independently of level populations, and experimentally establish quantitative relations linking battery capacity to von Neumann, Tsallis and linear entropies. By introducing a controlled dephasing channel with a magnetic-field gradient, we observe a monotonic reduction of capacity with coherence loss and track the corresponding evolution of the entropy-capacity relations. Our results identify thermal atomic spin ensembles as a scalable platform for quantum batteries and connect macroscopic quantum energy storage with operational quantum thermodynamics.
title Thermal vapor quantum battery based on collective atomic spins
topic Quantum Physics
url https://arxiv.org/abs/2604.17518