Bethe ansatz and thermodynamics of a SU(2)k factorizable S-matrix

Marcio Jose Martins, C.S. Melo

Koberle Roland

Lecture notes on factorizable S-matrices, thermodynamic Bethe Ansatz and integrable perturbations of conformally invariant models; J.A.Swieca Summer School 1991

C.S. Melo, Marcio Jose Martins

We consider the eigenspectrum solution of a many-body problem of interacting spin- s particles that can be solvable within the generalized Bethe ansatz method. We assume that the interactions are encoded in terms of an arbitrary U (1) invariant factorizable S -matrix. The exact solution of the spin part is based on a unified formulation of the quantum inverse scattering method for an arbitrary (2 s + 1)-dimensional monodromy matrix. The respective eigenstates are shown to be given in terms of 2 s creation fields by a general new recurrence relation. This allows us to derive the spectrum and the respective Bethe ansatz equations.

R. S. Banerjee

Marcio Jose Martins

We relate the complex solutions of the thermodynamic Bethe-ansatz equations to the excited states in factorizable massive models. This approach permits one to recover exactly the ultraviolet behavior of these excitations. In order to illustrate our method we consider several unitary and nonunitary integrable models. We also comment on the calculation of critical exponents in massless integrable models.

Minoru Takahashi