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DOE OSTI · 1647653

Superdiffusion from Emergent Classical Solitons in Quantum Spin Chains

De Nardis, Jacopo·Gopalakrishnan, Sarang·Ilievski, Enej·Vasseur, Romain
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Abstract

Finite-temperature spin transport in the quantum Heisenberg spin chain is known to be superdiffusive, and has been conjectured to lie in the Kardar-Parisi-Zhang (KPZ) universality class. Using a kinetic theory of transport, we compute the KPZ coupling strength for the Heisenberg chain as a function of temperature, directly from microscopics; the results agree well with density-matrix renormalization group simulations. Here, we establish a rigorous quantum-classical correspondence between the “giant quasiparticles” that govern superdiffusion and solitons in the classical continuous Landau-Lifshitz ferromagnet. We conclude that KPZ universality has the same origin in classical and quantum integrable isotropic magnets: a finite-temperature gas of low-energy classical solitons.

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1-dimensional spin chains75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITYKardar-Parisi-Zhang equationSolitonsTransport phenomena

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De Nardis, Jacopo, Gopalakrishnan, Sarang, Ilievski, Enej, Vasseur, Romain. 2020-08-12. Superdiffusion from Emergent Classical Solitons in Quantum Spin Chains. https://doi.org/10.1103/physrevlett.125.070601

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