超越经典热力学精度极限的量子热机

中文摘要 AI 辅助

非平衡过程中的精度伴随着热力学代价：抑制涨落通常需要增加耗散。热力学不确定关系（TURs）通过将电流涨落与经典随机动力学中的熵产生联系起来，使这种权衡得以定量化。自该关系发现以来的十年间，稳态TUR及其有限时间推广已成为非平衡热力学的基石，约束着分子机器的性能，并允许从可观测的涨落中推断热耗散。在受控量子器件中能否违反经典TUR仍是一个悬而未决的实验问题，部分原因在于这需要分辨极小的稳态电流及其涨落。在此，我们通过实验证明，稳态量子输运可以超越经典TUR所允许的精度。我们在一个超导量子热机中观察到这一违反现象，该热机与作为冷浴的微波波导以及提供有效无限温度浴的经典噪声源耦合。我们观测到TUR比率 $Q = 1.71 \pm 0.17$，违反了经典界限 $Q \geq 2$。我们的结果展示了经典热力学与量子热力学之间的根本区别，为以更低能量成本实现更高精度的量子热器件铺平了道路。

英文摘要

Precision in nonequilibrium processes comes at a thermodynamic cost: suppressing fluctuations generally requires increased dissipation. Thermodynamic uncertainty relations (TURs) make this trade-off quantitative by linking current fluctuations to entropy production in classical stochastic dynamics. In the decade since its discovery, the canonical steady-state TUR and its finite-time generalizations have become a cornerstone of non-equilibrium thermodynamics, constraining the performance of molecular machines and allowing heat dissipation to be inferred from observable fluctuations. Whether the canonical TUR can be violated in a controlled quantum device remains an outstanding experimental question, in part because doing so requires resolving extremely small steady-state currents as well as their fluctuations. Here we experimentally show that steady-state quantum transport can surpass the precision permitted by the canonical TUR. We observe this violation in a superconducting quantum thermal machine coupled to a microwave waveguide acting as a cold bath and to a classical noise source providing an effective infinite-temperature bath. We observe a TUR ratio $Q = 1.71 \pm 0.17$, in violation of the classical bound $Q \geq 2$. Our results demonstrate a fundamental distinction between classical and quantum thermodynamics, paving the way for quantum thermal devices that achieve enhanced precision at reduced energy cost.

发表机构

• Chalmers University of Technology（查尔姆斯理工大学）
• Trinity College Dublin（都柏林三一学院）
• King’s College London（伦敦国王学院）

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