Partial delocalization of the ground state by repulsive interactions in a disordered chain

The ground state of one-dimensional spinless fermions with short-range repulsion and strong disorder is studied numerically with the density matrix renormalization group method. At half filling, the limits of small and large interaction strength correspond, respectively, to the Anderson and Mott insulators. The charge reorganizations occurring for intermediate interaction lead to an enhanced sensitivity with respect to the boundary conditions, indicating a partial delocalization effect which persists in the thermodynamic limit.