Thermal diffusivity and chaos in metals without quasiparticles

Understand

We study the thermal diffusivity $D_T$ in models of metals without quasiparticle excitations (`strange metals').

• The many-body quantum chaos and transport properties of such metals can be efficiently described by a holographic representation in a gravitational theory in an emergent curved spacetime with an additional spatial dimension.
• We find that at generic infra-red fixed points $D_T$ is always related to parameters characterizing many-body quantum chaos: the butterfly velocity $v_B$, and Lyapunov time $\tau_L$ through $D_T \sim v_B^2 \tau_L$.
• The relationship holds independently of the charge density, periodic potential strength or magnetic field at the fixed point.