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Anomalous transport from hot quasiparticles in interacting spin chains
Sarang Gopalakrishnan1,2, Romain Vasseur3
1Department of Physics, The Pennsylvania State University, University Park, PA 16802, United States of America.
Reports on Progress in Physics. Physical Society (Great Britain)
|January 16, 2023
Summary
Quantum spin chains exhibit surprising spin transport properties, behaving diffusively or superdiffusively despite ballistic energy spread. Generalized hydrodynamics explains these anomalous transport phenomena through quasiparticle excitations.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
- Statistical Mechanics
Background:
- Experimentally relevant quantum spin chains often exhibit approximate integrability.
- These systems support long-lived quasiparticle excitations, crucial for understanding their dynamics.
- The XXZ spin chain is a canonical model demonstrating complex transport behaviors.
Purpose of the Study:
- To review the transport properties of the integrable XXZ spin chain.
- To explain anomalous spin transport using a quasiparticle picture and generalized hydrodynamics.
- To discuss recent developments in quantum spin chain transport.
Main Methods:
- Review of theoretical frameworks, focusing on generalized hydrodynamics.
- Analysis of quasiparticle excitation dynamics in integrable and near-integrable systems.
- Discussion of linear and non-linear response, full-counting statistics, and far-from-equilibrium transport.
Main Results:
- Energy spreads ballistically in the XXZ spin chain, while spin transport can be diffusive or superdiffusive.
- Anomalous linear response properties arise from quasiparticle hierarchies and hydrodynamic fluctuations.
- Generalized hydrodynamics provides an intuitive framework for understanding these phenomena.
Conclusions:
- The study provides a comprehensive overview of transport in XXZ spin chains.
- Recent theoretical and experimental advancements offer new insights into quantum spin transport.
- Understanding these properties is key for developing quantum technologies.
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