Instability of subdiffusive spin dynamics in strongly disordered Hubbard chain

Abstract

We study spin transport in a Hubbard chain with strong, random, on--site potential and with spin--dependent hopping integrals, $t_{\sigma }$. For the the SU(2) symmetric case, $t_{\uparrow }=t_{\downarrow }$, such model exhibits only partial many-body localization with localized charge and (delocalized) subdiffusive spin excitations. Here, we demonstrate that breaking the SU(2) symmetry by even weak spin--asymmetry, $t_{\uparrow }\ne t_{\downarrow }$, localizes spins and restores full many-body localization. To this end we derive an effective spin model, where the spin subdiffusion is shown to be destroyed by arbitrarily weak $t_{\uparrow }\ne t_{\downarrow }$. Instability of the spin subdiffusion originates from an interplay between random effective fields and singularly distributed random exchange interactions.

accepted as a Rapid Communication in Physical Review B

References in corpus (15)

• Localization of interacting fermions at high temperature
• Many-body localization edge in the random-field Heisenberg chain
• Many body localization in Heisenberg XXZ magnet in a random field
• Phenomenology of fully many-body-localized systems
• Many-body localization in periodically driven systems
• Anomalous diffusion and Griffiths effects near the many-body localization transition
• Absence of diffusion in an interacting system of spinless fermions on a one-dimensional disordered lattice
• Anomalous thermalization in ergodic systems
• Quantum quenches in the many-body localized phase
• Many-body mobility edge in a mean-field quantum spin glass
• Quantum revivals and many-body localization
• Many-body localization due to random interactions
• Purification and many-body localization in cold atomic gases
• Absence of full many-body localization in the disordered Hubbard chain
• Universal dynamics of density correlations at the transition to many-body localized state