Energy Currents in the Disordered XYZ Spin Chain

The delocalized region preceding the many-body localization (MBL) transition is currently receiving a significant amount of attention due to apparent deviations from typical diffusive transport. The XXZ spin chain has been shown to exhibit subdiffusive spin transport at intermediate disorder strengths, and the nature of energy transport close to the MBL transition is still a matter of debate.

We present results of a combined time-evolving block decimation and exact diagonalization study of energy currents in the disordered XYZ spin chain on the delocalized side of the MBL transition. The significance of this choice of model is that its clean hydrodynamics involves only energy currents, whereas the XXZ model has both energy and spin currents. This allows us to explore the question of how the nature of the delocalized phase depends on the hydrodynamic properties of the underlying clean model.