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Planckian Bound on Quantum Dynamical Entropy
1Université Paris Cité, Sorbonne Université, CNRS, Université PSL, Laboratoire de Physique de l'École normale supérieure, ENS, F-75005 Paris, France.
Physical Review Letters
|July 31, 2026
Summary
We present a simplified quantum dynamical entropy to measure information gained from monitoring quantum systems. A universal Planckian bound is conjectured for the entropy rate in many-body systems.
Area of Science:
- Quantum Information Theory
- Statistical Mechanics
- Condensed Matter Physics
Background:
- The Connes-Narnhofer-Thirring quantum dynamical entropy quantifies information gain from continuous observation.
- Understanding information dynamics in many-body quantum systems is crucial.
Purpose of the Study:
- Introduce a simplified quantum dynamical entropy measure.
- Investigate entropy growth rates in generic many-body systems.
- Conjecture a universal bound for entropy rates.
Main Methods:
- Developed a simplified quantum dynamical entropy.
- Analyzed thermal fluctuations of extensive observables.
- Computed entropy rates using two-point correlation functions in thermodynamic and long-time limits.
Main Results:
- Demonstrated nonzero entropy growth rates in generic many-body systems.
- Explicitly calculated entropy rates.
- Obtained related results for purification rates.
Conclusions:
- The simplified entropy provides a tractable measure for quantum information dynamics.
- A universal Planckian bound for entropy rate is conjectured.
- The findings are relevant for understanding information flow in quantum systems.
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