This paper examines whether quantum coherence is a physically enforcing resource for energy storage in closed quantum systems. Using a strict logical-necessity framework, it separates transient charging processes from the stationary post-charging storage state and applies enforcement and removal tests grounded only in physical mechanisms. By holding the Hamiltonian spectrum and population ordering fixed, the analysis shows that removing coherence after charging does not alter stored energy or extractable work. The paper therefore establishes that, in closed systems, quantum coherence does not enforce energy retention and that observed storage enhancements arise from spectral structure rather than coherence itself.
This paper examines whether quantum coherence is a physically enforcing resource for energy storage in closed quantum systems. Using a strict logical-necessity framework, it separates transient charging processes from the stationary post-charging storage state and applies enforcement and removal tests grounded only in physical mechanisms. By holding the Hamiltonian spectrum and population ordering fixed, the analysis shows that removing coherence after charging does not alter stored energy or extractable work. The paper therefore establishes that, in closed systems, quantum coherence does not enforce energy retention and that observed storage enhancements arise from spectral structure rather than coherence itself.
This paper examines the physical validity of treating internal quantum energy retention as equivalent to classical energy storage. Using a strict logical-necessity framework, it tests whether retained quantum excitations enforce work, force, or energy transfer across a system boundary during operation. By fixing the system boundary and applying conservation laws and eliminative removal tests, the paper shows that internal quantum subsystems only redistribute pre-existing energy and do not constitute physically enforcing storage mechanisms. The analysis isolates and rejects the implicit assumption of storage equivalence that underlies many quantum battery claims, without disputing experimental observations, coherence effects, or internal dynamics.
This paper identifies what physical enforcement reduces to when stripped to pure quantum physics. Using a strict logical-necessity framework and excluding observers, measurement, mathematics, and interpretation, it shows that persistent constraints can exist only through ongoing interaction that suppresses otherwise allowed quantum transitions. That suppression necessarily involves coupling, back-reaction, and dissipation; when interaction is removed, constraints immediately fail. The result isolates physical enforcement as an active, energy-consuming process at the quantum level and rules out passive or cost-free notions of laws or constraints.
Quantum batteries have recently emerged as promising candidates for microscopic energy-storage technologies exploiting uniquely quantum mechanical effects. In this work, we introduce the concept of a quantum capacitor, a coherence-based quantum energy-storage device exhibiting reversible and ultrafast charging-discharging dynamics. Unlike conventional quantum batteries, which primarily focus on extractable work, the proposed quantum capacitor operates through reactive energy accumulation mediated by coherent quantum polarization. We formulate a theoretical framework based on a driven two-level system and define a dynamical quantum capacitance associated with the response of stored energy to coherent external driving. The charging power, reversible energy exchange, and the effects of environmental decoherence are investigated analytically within the Lindblad formalism. We extend the proposal to interacting many-body systems and show that collective coherence and interactions can enhance the effective quantum capacitance and charging power, potentially leading to cooperative energy-storage advantages beyond the single-qubit regime.
This paper isolates and tests a single foundational assumption in quantum energy discussions: that probabilistic potential—such as decay likelihood, extractability, or transition rates—constitutes present physical enforcement. Using a strict logical-necessity framework, it distinguishes between descriptive probability and mechanically active processes by applying enforcement, removal, and invariance tests grounded only in physical interaction. The analysis demonstrates that probabilities and potentials do not, by themselves, apply force, exchange energy or momentum, or produce reciprocal back-reaction at the present instant. Therefore, they cannot be treated as physically enforcing entities without introducing an unexamined assumption. The paper resolves this issue by elimination, not reinterpretation, and leaves only physically enforced structure.
We investigate the charging dynamics and thermodynamic performance of a wireless quantum battery system mediated by a common structured bosonic environment. By employing a unified resource-theoretic analysis, we elucidate the distinct roles of non-Markovian memory effects and coupling symmetry in regulating energy transfer. In the Markovian weak-coupling regime, we identify a transformative mechanism where the dynamic reconstruction of l1-norm coherence compensates for the monotonic decay of first-order coherence to sustain energy transport. Conversely, the non-Markovian strong-coupling regime facilitates a cooperative resonance, characterized by the synchronized oscillation of entanglement and stored energy induced by environmental backflow. Furthermore, we reveal that coupling symmetry acts as a critical control parameter: while asymmetric coupling favoring the battery optimizes energy gain in memoryless environments, symmetric coupling under strong interactions unlocks a dark-state protection mechanism, effectively trapping energy within a decoherence-free subspace. Finally, a thermodynamic analysis based on ergotropy demonstrates that first-order coherence establishes the activation threshold for incoherent work, whereas l1-norm coherence serves as the explicit fuel for coherent work extraction. These findings provide a refined theoretical framework for engineering environment-assisted quantum energy storage devices.
Quantum batteries, which use quantum systems to store and deliver energy,
are promising for next-generation energy storage. However, optimizing charging
strategies and understanding the interplay between dissipation and quantum
coherence remain open challenges. Here, we investigate steady-state charging
in an open quantum battery and demonstrate that the charging timescale depends
on the spectral gap of the Liouvillian operator governing dissipative dynamics.
As a minimal example, we examine a three-level quantum battery realized in
a single trapped 40Ca+ ion, where energy from an
engineered thermal photon reservoir is coherently transferred to a long-lived
metastable storage state. We find that long-term dynamics are confined to
a low-dimensional manifold of slow Liouvillian modes, with their
spectral structure determining the relaxation rate to the charged
steady state. By adjusting experimentally accessible parameters,
such as reservoir occupation and coherent coupling strength, the non-Hermitian
Liouvillian spectrum can approach an exceptional point. This increases
the spectral gap and accelerates the approach to steady state. As a result,
this mechanism significantly enhances asymptotic charging power without
relying on many-body collectivity or steady coherence. Our findings offer
fundamental insights into open quantum thermodynamics and provide a path
to efficient energy storage and fast-charging solutions in emerging quantum
technologies.