Dieball Cai, Godec Aljaž
Mathematical bioPhysics Group, <a href="https://ror.org/03e76ya46">Max Planck Institute for Multidisciplinary Sciences</a>, 37077 Göttingen, Germany.
Phys Rev Lett. 2024 Aug 9;133(6):067101. doi: 10.1103/PhysRevLett.133.067101.
We prove that the transport of any differentiable scalar observable in d-dimensional nonequilibrium systems is bounded from above by the total entropy production scaled by the amount the observation "stretches" microscopic coordinates. The result-a time-integrated generalized speed limit-reflects the thermodynamic cost of transport of observables, and places underdamped and overdamped stochastic dynamics on equal footing with deterministic motion. Our work allows for stochastic thermodynamics to make contact with bulk experiments, and fills an important gap in thermodynamic inference, since microscopic dynamics is, at least for short times, underdamped. Requiring only averages but not sample-to-sample fluctuations, the proven transport bound is practical and applicable not only to single-molecule but also bulk experiments where only averages are observed, which we demonstrate by examples. Our results may facilitate thermodynamic inference on molecular machines without an obvious directionality from bulk observations of transients probed, e.g., in time-resolved x-ray scattering.
我们证明，在d维非平衡系统中，任何可微标量可观测量的输运在上方受到总熵产生的限制，总熵产生由观测对微观坐标的“拉伸”量进行缩放。该结果——一个时间积分的广义速度极限——反映了可观测量输运的热力学成本，并使欠阻尼和过阻尼随机动力学与确定性运动处于平等地位。我们的工作使得随机热力学能够与宏观实验建立联系，并填补了热力学推断中的一个重要空白，因为微观动力学至少在短时间内是欠阻尼的。所证明的输运界限仅要求平均值而非样本间波动，既实用又适用于不仅单分子而且仅观测平均值的宏观实验，我们通过实例进行了展示。我们的结果可能有助于从例如时间分辨X射线散射探测的瞬态宏观观测中，对没有明显方向性的分子机器进行热力学推断。
