发表机构
International Centre for Theory of Quantum Technologies, University of Gdańsk（格但斯克大学量子理论国际中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究探究孤立有限系统的热力学不可逆性，推导熵率并分离熵扩散与返回流，发现不可逆性源于信息无法组织恢复宏观有序的流，而非微观信息丢失。
AI 中文摘要
微观幺正动力学保留所有精细信息，但孤立有限系统可呈现出稳健的热力学窗口，其中与受限记录相关的熵会上升。我们探究为何当前记录隐藏的信息通常无法重建低熵宏观态。对于固定的投影记录，每一步有限演化可精确分解为仅由记录预测的演化，以及由未解决的微观结构携带的精确修正。仅记录的贡献在时间二阶项才开始出现，因此记录的所有瞬时变化都来自宏观态之间的隐藏流。我们推导了精确的熵率，将熵扩散与面向返回的流分离，并将这些流分解为能隙振幅。具有相同能隙的跃迁相干叠加，揭示了哈密顿量和微观态如何组织隐藏信息以实现返回。在相互作用混合动力学中，流功率分布在多个频率上；自由且刻意协调的控制会逐渐将其集中，工程化的动力学可重建低熵宏观态。一项独立的分布级测试将隐藏的动力学活动与有限步返回分离，且精确的经典保测对应物揭示了该构造的哪些部分并非唯一量子的。因此，在指定的记录和观测窗口内，不可逆性并非微观信息的丢失，而是该信息无法组织起恢复宏观有序性的流。
英文摘要
Microscopic unitary dynamics preserves all fine information, yet an isolated finite system can show a robust thermodynamic window in which the entropy associated with a restricted record rises. We ask why information hidden from the current record usually fails to rebuild a low-entropy macrostate. For a fixed projective record, every finite step separates exactly into the evolution predicted from the record alone and an exact correction carried by unresolved microscopic structure. The record-only contribution starts only at second order in time, so all instantaneous change of the record comes from hidden currents between macrostates. We derive the exact entropy rate, separate entropy-spreading from return-oriented currents, and resolve those currents into energy-gap amplitudes. Transitions with the same gap add coherently, revealing how the Hamiltonian and the microscopic state organize hidden information for return. In interacting mixing dynamics the current power is spread over many frequencies; free and deliberately commensurate controls progressively concentrate it, and the engineered dynamics reconstructs a low-entropy macrostate. An independent distribution-level test separates hidden dynamical activity from finite-step return, and an exact classical measure-preserving counterpart shows which parts of the construction are not uniquely quantum. Within the specified record and observation window, irreversibility is therefore not loss of microscopic information, but the failure of that information to organize currents that restore macroscopic order.
