Geometric power capacity of coherent ergotropy in quantum batteries
Abstract
We explore coherent ergotropy extraction in quantum batteries from a resource-geometric point of view. For an initial state ρ, we quantify the coherent extraction process by the coherent ergotropy ℰc(ρ) and the coherent extraction distance Dcext(ρ) between the active state σρ and the passive state Pρ. This defines the geometric power capacity Πc(ρ)=ℰc(ρ)/Dcext(ρ), which measures the coherent ergotropy released unit minimal unitary distance. We prove that, for any driving Hamiltonian satisfying |Vt|≤ν, the actual coherent discharging power is bounded by Pcext(ρ;Vt)≤ νΠc(ρ), showing that Πc(ρ) is a capacity under unit driving norm rather than the power of a particular protocol. General bounds on Πc(ρ) are derived by combining relative entropy bounds on coherent ergotropy with geometric bounds on the coherent extraction distance. We also formulate coherence measure induced bounds and protocol-corrected capacities involving the effective speed of a given Hamiltonian. Qubit and qutrit examples demonstrate that Πc(ρ) captures a resource-geometric feature of coherent discharging beyond coherent ergotropy or coherence measures alone.
Versions
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BibTeX
@misc{xuan2026geometric,
title = {{Geometric power capacity of coherent ergotropy in quantum batteries}},
author = {Dong-Ping Xuan and Hua Nan and Zhi-Xi Wang and Shao-Ming Fei},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.16645},
eprint = {2607.16645},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.16645},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Geometric power capacity of coherent ergotropy in quantum batteries
AU - Dong-Ping Xuan
AU - Hua Nan
AU - Zhi-Xi Wang
AU - Shao-Ming Fei
PY - 2026
DA - 2026/10/17
PB - arXiv
DO - 10.48550/arxiv.2607.16645
UR - https://arxiv.org/abs/2607.16645
AB - We explore coherent ergotropy extraction in quantum batteries from a resource-geometric point of view. For an initial state ρ, we quantify the coherent extraction process by the coherent ergotropy ℰ_c(ρ) and the coherent extraction distance D_c^ext(ρ) between the active state σ_ρ and the passive state P_ρ. This defines the geometric power capacity Π_c(ρ)=ℰ_c(ρ)/D_c^ext(ρ), which measures the coherent ergotropy released unit minimal unitary distance. We prove that, for any driving Hamiltonian satisfying |V_t|≤ν, the actual coherent discharging power is bounded by P_c^ext(ρ;V_t)≤ νΠ_c(ρ), showing that Π_c(ρ) is a capacity under unit driving norm rather than the power of a particular protocol. General bounds on Π_c(ρ) are derived by combining relative entropy bounds on coherent ergotropy with geometric bounds on the coherent extraction distance. We also formulate coherence measure induced bounds and protocol-corrected capacities involving the effective speed of a given Hamiltonian. Qubit and qutrit examples demonstrate that Π_c(ρ) captures a resource-geometric feature of coherent discharging beyond coherent ergotropy or coherence measures alone.
ER -