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 finitesize 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.