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arxiv: 2605.09527 · v1 · submitted 2026-05-10 · 🪐 quant-ph

Quantum Capacitor: A Coherence-Based Quantum Energy Storage Device

Saeed Haddadi This is my paper

Pith reviewed 2026-05-12 04:35 UTC · model grok-4.3

classification 🪐 quant-ph
keywords quantum capacitorquantum batterytwo-level systemquantum coherenceenergy storagequantum thermodynamicscoherent charging
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The pith

A driven two-level quantum system stores energy reactively through coherence, defining a quantum capacitance as the response of that energy to external driving.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper introduces a quantum capacitor as a device for reversible, ultrafast energy storage and release based on coherent polarization in a minimal driven two-level system. It defines quantum capacitance through the susceptibility of stored coherent energy to the driving field, shifting emphasis from extractable work to reactive accumulation and rapid discharge. The framework examines charging dynamics that produce coherent oscillations and accounts for how environmental decoherence affects performance. This setup connects principles of quantum coherence directly to the design of nanoscale energy-storage components.

Core claim

By modeling a driven two-level system, the work shows that energy can accumulate in the form of quantum coherence and respond to an external drive in a capacitive manner. Quantum capacitance is introduced as the measure of how this stored energy changes with the driving parameter, producing oscillatory charging behavior and enabling fast discharge without requiring population inversion.

What carries the argument

Quantum capacitance, defined as the susceptibility of coherent energy storage to external driving in a driven two-level system.

If this is right

  • Charging proceeds via coherent oscillations rather than incoherent excitation.
  • Rapid discharge becomes possible through the same coherent polarization channel.
  • Decoherence acts as a time limit on usable storage but does not remove the underlying capacitive response.
  • The model supplies a quantitative bridge between coherence measures and energy-storage metrics at the nanoscale.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Similar capacitive behavior might appear in other driven quantum systems such as superconducting circuits or trapped ions if coherence times allow.
  • Device metrics could be added to existing quantum battery analyses to compare reactive versus ergotropic performance.
  • Hybrid quantum-classical circuits might incorporate such elements for local, on-chip energy buffering.

Load-bearing premise

A physical realization of the driven two-level system must preserve enough coherence for reactive energy accumulation and rapid discharge to occur before decoherence dominates.

What would settle it

Drive a two-level system at varying amplitudes and frequencies, then check whether the measured energy exhibits an oscillatory component that scales with the driving strength without net population inversion or immediate loss to the environment.

read the original abstract

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 quantum device designed for reversible and ultrafast energy storage and release through coherent quantum polarization. Unlike conventional quantum batteries, whose primary focus is maximizing extractable work, the proposed quantum capacitor emphasizes reactive energy accumulation, coherence-assisted charging, and rapid discharge dynamics analogous to classical capacitive systems. We formulate a minimal theoretical framework based on a driven two-level system and define a quantum capacitance associated with the susceptibility of stored energy to external driving. We further discuss charging dynamics, coherent oscillatory behavior, and the role of environmental decoherence. Our proposal establishes a bridge between quantum thermodynamics, quantum coherence theory, and nanoscale energy-storage architectures.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 0 minor

Summary. The manuscript introduces the quantum capacitor as a coherence-based energy storage device using a driven two-level system model. It defines quantum capacitance via the susceptibility of stored energy to external driving, emphasizing reactive energy accumulation, coherence-assisted charging, and rapid discharge dynamics. The work outlines charging dynamics, coherent oscillations, and decoherence effects to bridge quantum thermodynamics with nanoscale energy architectures, positioning it as distinct from work-maximizing quantum batteries.

Significance. If the proposed framework were developed with explicit derivations and validated against decoherence, it could offer a useful conceptual bridge in quantum energy storage by highlighting capacitive analogs that exploit coherence for ultrafast reactive storage. This might stimulate theoretical and experimental work in quantum optics or superconducting circuits focused on polarization-based energy management rather than ergotropy extraction.

major comments (1)
  1. [Abstract] Abstract: The manuscript claims to 'formulate a minimal theoretical framework based on a driven two-level system' and to 'define a quantum capacitance associated with the susceptibility of stored energy to external driving,' yet supplies no Hamiltonian, energy functional, susceptibility expression, or derivation. Without these, the central claims on charging dynamics, coherent oscillatory behavior, and decoherence resistance cannot be assessed and remain unverified.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their thoughtful review and positive assessment of the conceptual contribution. We address the single major comment below and will incorporate the requested details in a revised manuscript.

read point-by-point responses

  1. Referee: [Abstract] Abstract: The manuscript claims to 'formulate a minimal theoretical framework based on a driven two-level system' and to 'define a quantum capacitance associated with the susceptibility of stored energy to external driving,' yet supplies no Hamiltonian, energy functional, susceptibility expression, or derivation. Without these, the central claims on charging dynamics, coherent oscillatory behavior, and decoherence resistance cannot be assessed and remain unverified.

    Authors: The referee correctly notes that the current manuscript presents the framework at a conceptual level without explicit derivations. In the revised version we will add: (i) the explicit Hamiltonian of the driven two-level system, (ii) the energy functional whose susceptibility defines the quantum capacitance, (iii) the closed-form expression for that susceptibility, and (iv) the step-by-step derivations of the charging dynamics, coherent oscillations, and decoherence effects. These additions will be placed in a new dedicated section immediately following the introduction, allowing direct verification of all claims. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The manuscript introduces a quantum capacitor concept via a minimal driven two-level system model and defines quantum capacitance through energy susceptibility to driving. No load-bearing derivations, equations, or predictions are exhibited that reduce by construction to fitted inputs or prior self-citations. The framework is presented as a definitional and modeling proposal grounded in standard quantum mechanics, with discussions of dynamics and decoherence remaining consistent with external benchmarks rather than internally forced. No self-definitional loops, renamed empirical patterns, or uniqueness theorems imported from overlapping authors appear in the provided text.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

The abstract provides no explicit free parameters, axioms, or invented entities beyond referencing a standard driven two-level system; the quantum capacitor and quantum capacitance are conceptual definitions rather than new physical postulates with independent evidence.

pith-pipeline@v0.9.0 · 5417 in / 1027 out tokens · 45320 ms · 2026-05-12T04:35:11.040650+00:00 · methodology

discussion (0)

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Reference graph

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