EXCITATION SPECTRUM AND CRITICAL EXPONENTS OF A ONE-DIMENSIONAL INTEGRABLE MODEL OF FERMIONS WITH CORRELATED HOPPING

We investigate the excitation spectrum of a model of N colour fermions with correlated hopping which can be solved by a nested Bethe ansatz. The gapless excitations of particle-hole type are calculated as well as the spin-wave like excitations which have a gap. Using general predictions of conformal field theory the long distance behaviour of some groundstate correlation functions are derived from a finite-size analysis of the gapless excitations. From the algebraic decay we show that for increasing particle density the correlation of so-called N-multiplets of particles dominates over the density-density correlation. This indicates the presence of bound complexes of these N-multiplets. This picture is also supported by the calculation of the effective mass of charge carriers.