Singular and nonsingular eigenvectors for the Gaudin model

Abstract

We present a method to construct a basis of singular and nonsingular common eigenvectors for Gaudin Hamiltonians in a tensor product module of the Lie algebra SL(2). The subset of singular vectors is completely described by analogy with covariant differential operators. The relation between singular eigenvectors and the Bethe Ansatz is discussed. In each weight subspace the set of singular eigenvectors is completed to a basis, by a family of nonsingular eigenvectors. We discuss also the generalization of this method to the case of an arbitrary Lie algebra.