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Error-Resilient Reversal of Quantum Chaotic Dynamics Enabled by Scramblons
Yu-Chen Li1, Tian-Gang Zhou2, Shengyu Zhang1,3
1University of Science and Technology of China, Laboratory of Spin Magnetic Resonance, School of Physical Sciences, Anhui Province Key Laboratory of Scientific Instrument Development and Application, Hefei 230026, China.
Physical Review Letters
|March 1, 2026
Summary
Researchers experimentally measured quantum chaos and information scrambling in a spin system. They developed a method to correct errors, revealing exponential chaos and extracting the quantum Lyapunov exponent for the first time.
Area of Science:
- Quantum Physics
- Condensed Matter Physics
- Quantum Information Science
Background:
- The arrow of time in quantum many-body systems arises from information scrambling and increasing entanglement during Hamiltonian evolution.
- Reversing quantum dynamics is theoretically possible but practically unstable due to exponential amplification of errors in backward evolution, a characteristic of quantum many-body chaos.
Purpose of the Study:
- To experimentally investigate information scrambling and quantum chaos in a macroscopic spin system.
- To validate predictions of scramblon theory, a framework for understanding quantum information scrambling.
- To develop and apply a protocol for mitigating errors in out-of-time-ordered correlator measurements.
Main Methods:
- Utilized solid-state nuclear magnetic resonance on a macroscopic ensemble of randomly interacting spins.
- Measured the out-of-time-ordered correlator (OTOC) to probe quantum information scrambling.
- Applied scramblon theory to identify and correct errors in the OTOC measurements caused by imperfect backward evolution.
Main Results:
- Successfully measured the OTOC and validated key predictions of scramblon theory.
- Demonstrated a method to isolate and mitigate experimental errors in the OTOC.
- Observed the expected exponential behavior of quantum many-body chaos and extracted the quantum Lyapunov exponent for the first time in an experimental many-body system.
Conclusions:
- The study provides the first experimental measurement of the quantum Lyapunov exponent in a many-body system.
- The developed protocol enhances dynamical reversibility in complex quantum systems by correcting errors in backward evolution.
- Results have significant implications for advancing quantum simulation, metrology, and understanding fundamental limits of quantum dynamics.
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