DMFT-QE Symposium: July 8

Talk 1:

Stark Many-Body Localization in Interacting Infinite Dimensional Systems

Guy Cohen, Tel Aviv University

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 DMFT and a combination of numerically exact and approximate techniques for solving the effective impurity problem. 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.

Talk 2:

Quasi-local entanglement witnesses across the Mott transition

Adriano Amaricci, Consiglio Nazionale delle Ricerche, Istituto Officina dei Materiali, SISSA

The development of concepts in quantum information theory provides us with new perspectives to explore the complex phases of correlated systems. Many of these phases are believed to originate from their proximity to the Mott insulating state, which gives it special significance. In this context, after a brief introduction to the key ideas of entanglement measures, I will address the emergence of strong quantum entanglement between nearby atomic orbitals within the Mott phase. By combining CDMFT methods with analytical tools from quantum information theory, I will review the interaction-driven Mott transition and the subsequent formation of pseudo-gap states upon doping, from the point of view of super-selected measures of entanglement and spatially separated pair-wise correlations.