We study theoretically the spin response functions using the relativistic many body theory. The spin response functions in the relativistic theory are reduced largely from the ones of the non-relativistic theory. This happens particularly to the longitudinal spin responses. This fact is able to remove the difficulty in reproducing the ratio of the longitudinal and transverse response functions ...

The many-body localization (MBL) proximity effect is an intriguing phenomenon where a thermal bath localizes due to the interaction with disordered system. interplay of and nonergodic behavior in these systems gives rise rich phase diagram, whose exploration active field research. In this paper, we study bosonic Hubbard model featuring two particle species representing Using state-of-the-art nu...