arXiv:1204.4037 · Journal of Physics A Mathematical and Theoretical
On form factors in nested Bethe Ansatz systems
Balázs Pozsgay, Willem-Victor van Gerven Oei, Márton Kormos
Abstract
We investigate form factors of local operators in the multi-component Quantum Non-linear Schrödinger model, a prototype theory solvable by the so-called nested Bethe Ansatz. We determine the analytic properties of the infinite volume form factors using the coordinate Bethe Ansatz solution and we establish a connection with the finite volume matrix elements. In the two-component models we derive a set of recursion relations for the "magnonic form factors", which are the matrix elements on the nested Bethe Ansatz states. In certain simple cases (involving states with only one spin-impurity) we obtain explicit solutions for the recursion relations.