近日，日本RIKEN量子计算中心(RQC)的Tan Van Vu与日本京都大学的Keiji Saito等人合作并取得一项新进展。经过不懈努力，他们揭示非平衡循环热机的几何特性。相关研究成果已于2024年4月12日在国际知名学术期刊《物理评论A》上发表。

该研究团队成功利用热机的几何长度和时间尺度，构建了功率与效率之间的权衡关系。值得一提的是，由于几何量在经典条件下可由实验直接测得，这种关系对于推断热力学效率具有实际价值。此外，研究人员进一步揭示了热机的功率始终受其几何长度与能量统计乘积的上界所限制。这项研究结果提供了循环热机性能的几何特征，其普遍适用于远离平衡态的经典和量子热机。

据悉，微观热机在理论和实验层面均受到了广泛关注。其中，关于功率和效率的基本限制，以及二者之间的权衡关系，已有深入研究。本研究旨在通过进一步探索循环热机在任意速度下运行时，其沿路径的几何长度与功率、效率之间的关系，从而进一步阐明热机的极限。

附：英文原文

Title: Geometric characterization for cyclic heat engines far from equilibrium

Author: Tan Van Vu, Keiji Saito

Issue&Volume: 2024/04/12

Abstract: Considerable attention has been devoted to microscopic heat engines in both theoretical and experimental aspects. Notably, the fundamental limits pertaining to power and efficiency, as well as the trade-off relations between these two quantities, have been intensively studied. This study aims to shed further light on the ultimate limits of heat engines by exploring the relationship between the geometric length along the path of cyclic heat engines operating at arbitrary speeds and their power and efficiency. We establish a trade-off relation between power and efficiency using the geometric length and the timescale of the heat engine. Remarkably, because the geometric quantity comprises experimentally accessible terms in classical cases, this relation is useful for the inference of thermodynamic efficiency. Moreover, we reveal that the power of a heat engine is always upper bounded by the product of its geometric length and the statistics of energy. Our results provide a geometric characterization of the performance of cyclic heat engines, which is universally applicable to both classical and quantum heat engines operating far from equilibrium.

DOI: 10.1103/PhysRevA.109.042209

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.042209