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Dynamical Transitions from Slow to Fast Relaxation in Random Open Quantum Systems
Dror Orgad1, Vadim Oganesyan2,3, Sarang Gopalakrishnan4
1Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel.
Physical Review Letters
|February 9, 2024
Summary
This study reveals three distinct dynamical phases in random quantum systems affected by noise, based on spatial locality. These phases dictate how quickly systems reach equilibrium, with implications for quantum information processing.
Area of Science:
- Quantum physics
- Condensed matter theory
- Quantum information science
Background:
- Understanding quantum systems under environmental noise is crucial for quantum technologies.
- Spatial locality effects in random quantum systems are not fully understood.
- Markovian noise dynamics are a common model for environmental interactions.
Purpose of the Study:
- To investigate how spatial locality influences the dynamics of random quantum systems subjected to Markovian noise.
- To identify different dynamical phases based on system parameters.
- To explore the role of noise strength and system size on relaxation dynamics.
Main Methods:
- Studied a model with random Hamiltonians and noise couplings exhibiting power-law decay with distance.
- Analyzed the spectrum of the Lindblad superoperator to determine system dynamics.
- Employed perturbation theory to examine phase boundaries and nonperturbative effects.
Main Results:
- Identified three dynamical phases characterized by the rate of approach to a featureless steady state.
- Discovered an asymptotically exponential relaxation phase due to a spectral gap.
- Found two gapless phases with subexponential relaxation, distinguished by gap behavior with system size.
- Perturbation theory suggested phase transitions with noise strength, but nonperturbative effects prevented them in the thermodynamic limit.
Conclusions:
- Spatial locality significantly impacts the relaxation dynamics of noisy quantum systems.
- The system exhibits distinct phases of relaxation, crucial for predicting its behavior.
- Thermodynamic limit effects suppress phase transitions predicted by simpler theories, highlighting the importance of nonperturbative analyses.
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