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Quantum criticality of hot random spin chains
R Vasseur1,2, A C Potter1, S A Parameswaran3
1Department of Physics, University of California, Berkeley, California 94720, USA.
Physical Review Letters
|June 13, 2015
Summary
Infinite quantum spin chains with strong disorder show nonergodic behavior, behaving like "quantum critical glasses." These systems exhibit novel phases distinct from ground states.
Area of Science:
- Condensed matter physics
- Quantum many-body systems
- Statistical mechanics
Background:
- Understanding the behavior of quantum systems at high temperatures is crucial for various fields.
- Disorder in quantum spin chains can lead to complex phenomena, including nonergodicity.
Purpose of the Study:
- To investigate the infinite-temperature properties of random quantum spin chains.
- To explore the emergence of nonergodic behavior and novel phases in these systems.
Main Methods:
- Real-space renormalization group approach.
- Analysis using SU(2)_{k} anyon chains, including Ising and Potts models.
- Examination of highly excited eigenstates and their properties.
Main Results:
- Demonstrated nonergodic behavior at strong disorder in infinite quantum spin chains.
- Identified highly excited eigenstates exhibiting properties of quantum critical ground states, termed "quantum critical glasses."
- Showed that random-bond Heisenberg chains self-thermalize, with excited-state entanglement crossing over from volume-law to logarithmic scaling.
Conclusions:
- The excited state fixed points are distinct from ground state counterparts, indicating novel nonequilibrium critical phases.
- The study provides insights into the nature of thermalization and critical phenomena in disordered quantum systems.
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