Hot band sound

Understand

Chaotic lattice models at high temperature are generically expected to exhibit diffusive transport of all local conserved charges.

• Such diffusive transport is usually associated with overdamped relaxation of the associated currents.
• Here we show that by appropriately tuning the inter-particle interactions, lattice models of chaotic fermions at infinite temperature can be made to cross over from an overdamped regime of diffusion to an underdamped regime of ``hot band sound''.
• We study a family of one-dimensional spinless fermion chains with long-range density-density interactions, in which the damping time of sound waves can be made arbitrarily long even as an effective interaction strength is held fixed.