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Initial-state-independent equilibration at the breakdown of the eigenstate thermalization hypothesis
Abdellah Khodja1, Daniel Schmidtke1, Jochen Gemmer1
1Fachbereich Physik, Universität Osnabrück, Barbarastrasse 7, D-49069 Osnabrück, Germany.
Physical Review. E
|May 14, 2016
Summary
Quantum chaos and thermalization in spin ladders are explored. Strong interactions violate the eigenstate thermalization hypothesis (ETH), leading to initial-state-dependent relaxation and a shift towards integrability.
Area of Science:
- Quantum physics
- Condensed matter theory
- Quantum chaos
Background:
- The eigenstate thermalization hypothesis (ETH) explains thermalization in isolated quantum systems.
- Understanding quantum chaos in systems without classical analogs is crucial.
- Initial state independent equilibration is a key aspect of thermalization.
Purpose of the Study:
- Investigate the interplay between ETH, equilibration, and quantum chaos.
- Explore these phenomena in asymmetric Heisenberg spin ladders.
- Analyze the impact of varying interaction strengths on system dynamics.
Main Methods:
- Numerical investigations of asymmetric Heisenberg spin ladders.
- Studying the relaxation dynamics of energy differences between spin legs.
- Computing two parameters to quantify adherence to ETH.
Main Results:
- Violation of ETH observed at large interaction strengths.
- Energy relaxation becomes dependent on the initial state above a critical interaction strength.
- Level statistics shift from Poisson-type to Wigner-type at this critical point.
Conclusions:
- Strong interactions in these spin ladders lead to ETH violation.
- The system exhibits a transition towards integrability in the strong interaction limit.
- This behavior is linked to the loss of initial state independence in equilibration.
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