Energy (and spin) transport in the thermal phase of the disordered Heisenberg chain

Who: Vipin Varma, International Center for Theoretical Physics
When: 
Thursday, April 28, 2016 - 4:30pm to 5:30pm
Where: 
Allen Hall 321
3941 O'Hara Street, Pittsburgh, PA 15260

We study energy transport at high temperature in the thermal phase of the disordered Heisenberg chain [1]. Starting from nonequilibrium initial conditions that are either well within linear response or well outside of it, we show that a phenomenological hydrodynamic description captures the mechanism for equilibration. In particular, an energy diffusion constant is identified which vanishes in the thermal phase even before the localisation transition: the thermal phase is separated into diffusive and subdiffusive regimes. If time permits, similar results will be shown to hold for the transport of spin [2]; in particular a critical length scale is seen to exist below which the disorder is irrelevant.

 

[1] V. K. Varma, A. Lerose, F. Pietracaprina, J. Goold, A. Scardicchio, arxiv 1511.09144

[2] M. Znidaric, A. Scardicchio, V. K. Varma, arxiv 16xx.xxxx