arXiv:cond-mat/0610559 · Journal of Statistical Mechanics Theory and Experiment
Nonlinear integral equations for the thermodynamics of thesl(4)-symmetric Uimin–Sutherland model
Jens Damerau, Andreas Klümper
Abstract
We derive a finite set of nonlinear integral equations (NLIE) for the thermodynamics of the one-dimensional sl (4)-symmetric Uimin–Sutherland model. Our NLIE can be evaluated numerically for arbitrary finite temperature and chemical potentials. We recover the NLIE for sl (3) as a limiting case. In comparison to other recently derived NLIE, the evaluation at low temperature poses no problem in our formulation. The model shows a rich ground-state phase diagram. We obtain the critical fields from the limit of our NLIE. As an example for the application of the NLIE, we give numerical results for the SU (4) spin–orbital model. The magnetic susceptibility shows divergences at critical fields in the low-temperature limit and logarithmic singularities for zero magnetic field.