Stark-Many body localization in interacting infinite dimensional systems

Author:

Hristiana Atanasova, André Erpenbeck, Emanuel Gull, Yevgeny Bar Lev, Guy Cohen

Keyword:

Condensed Matter, Disordered Systems and Neural Networks, Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el)

journal:

date:

2023-11-15 00:00:00

Abstract

We study bulk particle transport in a Fermi-Hubbard model on an infinite-dimensional Bethe lattice, driven by a constant electric field. Previous numerical studies showed that one dimensional analogs of this system exhibit a breakdown of diffusion due to Stark many-body localization (Stark-MBL) at least up to time which scales exponentially with the system size. Here, we consider systems initially in a spin density wave state using a combination of numerically exact and approximate techniques. We show that for sufficiently weak electric fields, the wave's momentum component decays exponentially with time in a way consistent with normal diffusion. By studying different wavelengths, we extract the dynamical exponent and the generalized diffusion coefficient at each field strength. Interestingly, we find a non-monotonic dependence of the dynamical exponent on the electric field. As the field increases towards a critical value proportional to the Hubbard interaction strength, transport slows down, becoming sub-diffusive. At large interaction strengths, however, transport speeds up again with increasing field, exhibiting super-diffusive characteristics when the electric field is comparable to the interaction strength. Eventually, at the large field limit, localization occurs and the current through the system is suppressed.

PDF: Stark-Many body localization in interacting infinite dimensional systems.pdf