An analysis of the $t_2-V$ model

Abstract

We study a model (i.e., the $t_2-V$ model involving {\em next-nearest-neighbor hopping} and nearest-neighbor repulsion) in one-dimension that generically depicts the dominant transport mechanism in cooperative strong electron-phonon interaction systems. Using analytic and numerical approaches, hard-core-bosons are shown to typically undergo a striking discontinuous transition from a superfluid to a supersolid. Topological inequivalence of rings with even and odd number of sites is manifested through observable differences (in structure factor peaks) at the transition. Connections are also identified between the $t_2-V$ model and other topologically interesting models.

This work is dedicated to the memory of Gabriele F. Giuliani. Accepted in Phys. Rev. B. More detailed presentation; results presented for the t_2-V model are related to those obtained for other models and previous findings