We investigate the generalized supersymmetric t− J model with boundary impurities in different gradings. All three different gradings: fermion, fermion, boson (FFB), boson, fermion, fermion (BFF) and fermion, boson, fermion (FBF), are studied for the generalized supersymmetric t − J model. Boundary K-matrix operators are found for the different gradings. By using the graded algebraic Bethe ansa...

We consider the case of an integrable quantum spin chain with “soliton non-preserving” boundary conditions. This is the first time that such boundary conditions have been considered in the spin chain framework. We construct the transfer matrix of the model, we study its symmetry and we find explicit expressions for its eigenvalues. Moreover, we derive a new set of Bethe ansatz equations by mean...

We found the eigenvalues of the transfer matrices for the 1-D Hubbard model and for the coupled XY model with twisted boundary condition by using the analytic Bethe Ansatz method. Under a particular condition the two models have the same Bethe Ansatz equations. We have also proved that the periodic 1-D Hubbard model is exactly equal to the coupled XY model with nontrivial twisted boundary condi...

We generalise the fusion procedure for the A (1) N−1 open spin chain (N > 2) and we show that the transfer matrix satisfies a crossing property. We use these results to solve the A (1) N−1 open spin chain with Uq (SU(N )) symmetry by means of the analytical Bethe ansatz method. Our results coincide with the known ones obtained via the nested Bethe ansatz.

Exact solutions for eigenvalues and eigenfunctions of some nuclear many-body systems are found by using an infinite-dimensional, Lie-algebraic approach based on the corresponding Bethe ansatz. Applications of the theory, including solutions of some nuclear pairing problems and U(5) W SO(6) transitional Hamiltonians of the interacting boson model, are given. The relationship between this new met...

We present a multi-grid algorithm in order to solve numerically the thermody-namic Bethe ansatz equations. We speciically adapt the program to compute the data of the conformal eld theory reached in the ultraviolet limit. Nature of the physical problem: resolve the thermodynamic Bethe ansatz equations corresponding to a factorized scattering theory and extract the data of the underlying conform...