Thermalization and Possible Signatures of Quantum Chaos in Complex Crystalline Materials

Abstract

Analyses of thermal diffusivity data on complex insulators and on strongly correlated electron systems hosted in similar complex crystal structures suggest that quantum chaos is a good description for thermalization processes in these systems, particularly in the high temperature regime where the many phonon bands and their interactions dominate the thermal transport. Here we observe that for these systems diffusive thermal transport is controlled by a universal Planckian time scale $\tau \sim \hslash /k_{B}T$, and a unique velocity $v_E$. Specifically, $v_E\approx v_{ph}$ for complex insulators, and $v_{ph}\lesssim v_E\ll v_F$ in the presence of strongly correlated itinerant electrons ($v_{ph}$ and $v_F$ are the phonons and electrons velocities respectively). For the complex correlated electron systems we further show that charge diffusivity, while also reaching the Planckian relaxation bound, is largely dominated by the Fermi velocity of the electrons, hence suggesting that it is only the thermal (energy) diffusivity that describes chaos diffusivity.

References in corpus (6)

• Theory of universal incoherent metallic transport
• Microscopic model of quantum butterfly effect: out-of-time-order correlators and traveling combustion waves
• Quantum chaos on a critical Fermi surface
• Indirect searches for sterile neutrinos at a high-luminosity Z-factory
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Cited by in corpus (4)

• Transport properties of strongly coupled electron-phonon liquids
• Universal Bounds on Transport in Holographic Systems with Broken Translations
• Strongly coupled quantum phonon fluid in a solvable model
• Quantum many-body physics from a gravitational lens