Original title: Thermodynamic Irreversibility from Inaccessible Endogenous Quantum Histories
Borhan Ahmadi · September 2026
In quantum physics, microscopic laws keep all information intact. Yet, when we track an isolated system using coarse observations, entropy, or disorder, still increases. Scientists wanted to know why this hidden information rarely brings the system back to an ordered state. They showed that every step of a system splits into what the record predicts plus a correction from hidden details. The record itself causes no immediate changes; hidden flows between macrostates drive all instantaneous change. The authors broke these currents down into energy gaps. In mixing systems, these flows spread across many frequencies, meaning they cannot steer the system back. However, carefully designed controls can focus these frequencies, successfully rebuilding a low-entropy state. Irreversibility does not mean information disappears. Instead, hidden information simply fails to align the flows needed to rebuild macroscopic order.
You're tidying up a messy kitchen, but you only have a partial list of where things were. Even though everything is still in the kitchen, without the full list, you can't reconstruct the original neat state. In this paper, the partial list is the projective record, and the hidden locations are the microscopic quantum states. The difficulty in restoring the kitchen mirrors how hidden information fails to organize currents to reverse entropy.
This work explains why isolated quantum systems can appear irreversible even though information isn't lost. It could affect the design of quantum technologies where controlling entropy is essential for performance.
The analysis is confined to a fixed projective record and observation window. It does not address open systems or other measurement types, and a classical counterpart shows which parts are not uniquely quantum.
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Thermodynamic Irreversibility from Inaccessible Endogenous Quantum Histories — Borhan Ahmadi
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.