Spinmediated particle transport in the disordered Hubbard model
Abstract
Motivated by the recent experiments that reported signatures of manybody localization of ultracold atoms in optical lattices [M. Schreiber et al., Science 349, 842 (2015), 10.1126/science.aaa7432], we study dynamics of highly excited states in the strongly disordered Hubbard model in one dimension. Owing to the S U (2 ) spin symmetry, spin degrees of freedom form a delocalized thermal bath with a narrow bandwidth. The spin bath mediates slow particle transport, eventually leading to delocalization of particles. The particle hopping rate is exponentially small in t /W (t ,W being hopping and disorder scales) owing to the narrow bandwidth of the spin bath. We find the optimal length scale for particle hopping and show that the particle transport rate depends strongly on the density of singly occupied sites in the initial state. The delocalization rate is zero for initial states with only doubly occupied or empty sites, suggesting that such states are truly manybody localized, and therefore the Hubbard model may host both localized and delocalized states. Full manybody localization can be induced by breaking spin rotational symmetry.
 Publication:

Physical Review B
 Pub Date:
 March 2019
 DOI:
 10.1103/PhysRevB.99.115111
 arXiv:
 arXiv:1808.05764
 Bibcode:
 2019PhRvB..99k5111P
 Keywords:

 Condensed Matter  Strongly Correlated Electrons;
 Condensed Matter  Disordered Systems and Neural Networks;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Quantum Gases
 EPrint:
 4+\epsilon\ pages, 3 figures