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arXiv 2602.22893quant-ph
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信息与相干性作为从未知量子态中提取功和提供量子优势的资源

Information and coherence as resources for work extraction from unknown quantum state and providing quantum advantages

Los Alamos National Laboratory（洛斯阿拉莫斯国家实验室）

Tanmoy Biswas

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AI总结：

研究揭示了相干性作为从未知量子态中提取功的关键资源，通过观测ergotropy分析展示了量子优势的来源。

摘要：

从物理系统中可提取的功与系统状态的可用信息量之间存在根本联系，如麦克斯韦妖和盖斯悖论所展示的。在标准热力学协议中，系统-浴相互作用的最大功由初始态与对应浴温度下的吉布斯态之间的自由能差给出。这促使一个自然问题：在不涉及热浴的闭合量子系统中，信息是否也限制通过单位ary操作获得的功？尽管ergotropy量化了通过unitary操作可提取的最大功，但其假设完全了解量子态，通常需要完整的态重构。然而在现实场景中，只有部分信息是可得的。在这种情况下，相关的度量标准是观测ergotropy，它明确依赖于用于探测系统的测量。我们证明观测ergotropy在经典后处理测量结果时会减少，这意味着细粒度测量允许比粗粒度测量更大的功提取。此外，对所有可能测量最大化观测ergotropy恢复标准ergotropy，它分解为无序（经典）和有序（量子）贡献。我们的结果表明，在测量投影器中的相干性构成关键资源，使功提取超越无序极限，并确立相干性作为观测ergotropy提取中量子优势的起源。

英文摘要：

The amount of extractable work from a physical system is fundamentally connected to the information available about its state, as illustrated by Maxwell's demon and the Gibbs paradox. In standard thermodynamic protocols involving system--bath interactions, the maximum work is given by the free-energy difference between the initial state and the corresponding Gibbs state at the bath temperature. This motivates a natural question: does information also limit work extraction in closed quantum systems that do not involve a heat bath and where work is obtained through unitary operations generated by a time-dependent Hamiltonian? While ergotropy quantifies the maximum work extractable via unitary operations, it assumes complete knowledge of the quantum state, typically requiring full state tomography. In realistic scenarios, however, only partial information is accessible. In this case, the relevant figure of merit is observational ergotropy, which depends explicitly on the measurement used to probe the system. We show that observational ergotropy decreases under classical post-processing of measurement outcomes, implying that fine-grained measurements allow greater work extraction than coarse-grained ones. Moreover, maximizing observational ergotropy over all possible measurements recovers standard ergotropy, which decomposes into incoherent (classical) and coherent (quantum) contributions. Our results demonstrate that coherence in the measurement projectors constitutes the key resource, enabling work extraction beyond the incoherent limit and establishing coherence as the origin of quantum advantage in observational ergotropy extraction.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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