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Published on: October 24, 2017
Measurement-Induced Phase Transition in the Monitored Sachdev-Ye-Kitaev Model
Shao-Kai Jian1, Chunxiao Liu2, Xiao Chen3
1Condensed Matter Theory Center and Joint Quantum Institute, Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
We study entanglement phase transitions in monitored Sachdev-Ye-Kitaev (SYK) chains. A key finding is that varying measurement rates can break symmetries, altering entanglement entropy scaling from area-law to log-scaling or volume-law.
Area of Science:
- Quantum Information Theory
- Condensed Matter Physics
- High Energy Physics
Background:
- The Sachdev-Ye-Kitaev (SYK) model describes quantum chaotic systems.
- Continuous monitoring introduces quantum trajectories and can drive phase transitions.
- Entanglement entropy scaling reveals critical properties of quantum many-body systems.
Purpose of the Study:
- To investigate entanglement phase transitions in monitored Brownian SYK chains.
- To analytically derive the effective action and understand the role of symmetry breaking.
- To characterize the different entanglement entropy scaling behaviors in various phases.
Main Methods:
- Analytical derivation of the effective action in the large-N limit.
- Exploration of symmetry breaking in an enlarged replica space.
- Numerical verification of critical exponents using Schwinger-Dyson equations.
Main Results:
- An entanglement transition is driven by symmetry breaking in the replica space.
- Non-interacting SYK2 chains exhibit O(2) symmetry breaking, leading to log-scaling entanglement entropy (vortices) or area-law scaling.
- Interacting SYK chains show C4 symmetry breaking, resulting in volume-law entanglement entropy due to domain wall costs.
Conclusions:
- Continuous monitoring of SYK chains can induce distinct entanglement phases.
- Symmetry breaking in replica space is the mechanism behind these entanglement transitions.
- The nature of the symmetry (continuous vs. discrete) dictates the resulting entanglement scaling laws.
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