arXiv subjects
Publications and source records attributed to A. Klümper.
We have found the exact groundstate for a large class of antiferromagnetic spin-1 models with nearest-neighbour interactions on a linear chain. All groundstate properties can be calculated. The groundstate is determined as a matrix product of individual site states and has the properties of the Haldane scenario.
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.