Thermalisation in hot disordered Heisenberg spin chains
We study the infinite-temperature properties of random Heisenberg spin chains. Our approach is based on strong disorder renormalization group (SDRG) method that we supplement by comprehensive analysis of resonant process not captured by the later. We show that upon increase of the system size the resonant process proliferate and destroy slowly thermalizing phase predicted by SDRG that can be observed in short systems. These findings should be contrasted to the zero-temperature case where we predict SDRG to capture correctly the ground-state properties of the system.