We study the many-body localization (MBL) transition in a generalized
Aubry-Andre model (also known as the GPD model) introduced in Phys. Rev. Lett.
114, 146601 (2015). In contrast to MBL in other disordered or quasiperiodic
models, the interaction seems to unexpectedly enhance MBL in the GPD model in
some parameter ranges. To understand this counter-intuitive result, we
demonstrate that the highest-energy single-particle band in the GPD model is
unstable against even infinitesimal disorder, which leads to this surprising
MBL phenomenon in the interacting model. We develop a mean-field theory
description to understand the coupling between extended and localized states,
which we validate using extensive exact diagonalization and DMRG-X numerical
results.Comment: 5 pages and 5 figures. Comments are welcom