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Quantum Error Correction in Scrambling Dynamics and Measurement-Induced Phase Transition.
Soonwon Choi1, Yimu Bao1, Xiao-Liang Qi2
1Department of Physics, University of California Berkeley, Berkeley, California 94720, USA.
Physical Review Letters
|August 4, 2020
Summary
We discovered two stable phases in open quantum systems, where information scrambling protects quantum information. A phase transition occurs when error rates exceed a threshold, impacting entanglement entropy dynamics.
Area of Science:
- Quantum Information Science
- Condensed Matter Physics
- Quantum Error Correction
Background:
- Entanglement entropy dynamics in open quantum systems are complex.
- Understanding these dynamics is crucial for quantum computing and information processing.
- Existing models often lack independent control over information scrambling and error rates.
Purpose of the Study:
- To analyze entanglement entropy dynamics in a generic quantum many-body open system.
- To introduce and study a novel random unitary circuit model with controllable parameters.
- To understand the role of information scrambling and projective measurements in phase transitions.
Main Methods:
- Developed a random unitary circuit model with intermittent projective measurements.
- Independently controlled information scrambling (unitary evolution) and error rates (projective measurements).
- Utilized numerical simulations to confirm theoretical predictions and map the phase diagram.
Main Results:
- Identified two stable phases characterized by volume-law and area-law scaling of entanglement entropy.
- Demonstrated that chaotic unitary evolution acts as a quantum error correction mechanism.
- Found a phase transition when error rates surpass a threshold dependent on information scrambling.
Conclusions:
- Information scrambling is critical for understanding entanglement dynamics in open quantum systems.
- The entanglement phase transition is linked to changes in quantum channel capacity.
- The model provides a framework for studying quantum information protection and error correction in realistic quantum systems.
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