ar X iv : h ep - t h / 96 11 00 5 v 1 1 N ov 1 99 6 SU ( N ) Matrix Difference Equations and a Nested Bethe Ansatz

/ 96 11 00 6 v 1 1 N ov 1 99 6 U ( N ) Matrix Difference Equations and a Nested Bethe Ansatz

A system of U(N)-matrix difference equations is solved by means of a nested version of a generalized Bethe Ansatz. The highest weight property of the solutions is proved and some examples of solutions are calculated explicitly.

ar X iv : h ep - t h / 92 11 12 4 v 1 2 6 N ov 1 99 2 Chiral Symmetry Breaking with the Curtis - Pennington Vertex

We study chiral symmetry breaking in quenched QED 4 , using a vertex Ansatz recently proposed by Curtis and Pennington. Bifurcation analysis is employed to establish the existence of a critical coupling and to estimate its value. The main results are in qualitative agreement with the ladder approximation, the numerical changes being minor.

ar X iv : h ep - t h / 94 10 11 8 v 2 2 2 N ov 1 99 4 WILSON LOOPS , qq̄ and 3 q POTENTIALS , BETHE – SALPETER EQUATION

ar X iv : h ep - p h / 96 11 30 6 v 1 1 2 N ov 1 99 6 INTRODUCTION TO THE POMERON 1

ar X iv : h ep - t h / 96 11 22 6 v 1 2 7 N ov 1 99 6 On the relations between osp ( 2 , 2 ) and the quasi exactly solvable systems

By taking a product of two sl(2) representations, we obtain the differential operators preserving some space of polynomials in two variables. This allows us to construct the representations of osp(2,2) in terms of matrix differential operators in two variables. The corresponding operators provide the building blocks for the construction of quasi exactly solvable systems of two and four equation...