Asymptotic Bethe-Ansatz results for a Hubbard Chain with 1/sinh-Hopping

Abstract

We investigate spin-1/2 electrons with local Hubbard interaction and variable range hopping amplitudes which decay like~$\sinh (\kappa )/\sinh (\kappa r)$. Assuming integrability the Asymptotic Bethe Ansatz approach allows us to derive the generalized Lieb-Wu integral equations from the two-particle phase shift. Due to the nesting property there is a metal-to-insulator transition at $U_c(\kappa >0)=0^{+}$. The charge gap in the singular limit $\kappa =0$ opens when the interaction strength equals the bandwidth, $U_c(\kappa =0)=W>0$.

9 pages, REVTeX; original manuscript rejected by PRL for non-scientific reasons -- this shortened version to to appear in Europhys. Lett. (1995)