近日，西班牙巴塞罗那大学的F. Ritort及其研究团队取得一项新进展。经过不懈努力，他们提出熵产生的方差和规则。相关研究成果已于2024年3月1日在国际权威学术期刊《科学》上发表。

该研究团队引入了位移和力方差的方差和规则(VSR)，使研究人员能够测量非平衡稳态下的熵产率σ。研究人员首先举例说明直接可测量的力，例如光学势阱中的活跃布朗粒子。然后，研究人员将VSR应用于人类红细胞的闪烁实验。研究人员发现σ在空间上是不均匀的，具有有限的相关长度，其平均值与量热测量值一致。VSR为利用力谱和时间分辨成像在生物和活性物质中推导σ铺平了道路。

据悉，熵的产生是非平衡物理的标志，量化不可逆性、耗散和能量传导过程的效率。尽管付出了许多努力，但在纳米尺度上进行测量仍然具有挑战性。

附：英文原文

Title: Variance sum rule for entropy production

Author: I. Di Terlizzi, M. Gironella, D. Herraez-Aguilar, T. Betz, F. Monroy, M. Baiesi, F. Ritort

Issue&Volume: 2024-03-01

Abstract: Entropy production is the hallmark of nonequilibrium physics, quantifying irreversibility, dissipation, and the efficiency of energy transduction processes. Despite many efforts, its measurement at the nanoscale remains challenging. We introduce a variance sum rule (VSR) for displacement and force variances that permits us to measure the entropy production rate σ in nonequilibrium steady states. We first illustrate it for directly measurable forces, such as an active Brownian particle in an optical trap. We then apply the VSR to flickering experiments in human red blood cells. We find that σ is spatially heterogeneous with a finite correlation length, and its average value agrees with calorimetry measurements. The VSR paves the way to derive σ using force spectroscopy and time-resolved imaging in living and active matter.

DOI: 10.1126/science.adh182

Source: https://www.science.org/doi/10.1126/science.adh1823