Particle Theory Seminar - Luca Delacretaz - “Bound on the thermalization time of d>2 CFTs”

Interacting systems thermalize. They can do so arbitrarily slowly, but not arbitrarily fast: the time scale necessary for a quantum many-body system to reach local thermal equilibrium has been conjectured to be bounded below by the Planckian time, \hbar/T. Using EFT approaches to hydrodynamics, I will argue for a “bottoms-up” proof of this bound for CFTs in spacetime dimensions d>2, by showing that the strong coupling scale of hydrodynamics must be lesser than the temperature T. The proof involves knowledge of power-law corrections to hydrodynamic correlators at late times, as well as causality constraints in the thermal state.