Signature Characters of Highest-Weight Representations of $U_{q}(\mathfrak {gl}_{n})$

Abstract

We consider $U_{q}(\mathfrak {gl}_{n})$ , the quantum group of type A for |q| = 1, q generic. We provide formulas for signature characters of irreducible finite-dimensional highest weight modules and Verma modules. In both cases, the technique involves combinatorics of the Gelfand-Tsetlin bases. As an application, we obtain information about unitarity of finite-dimensional irreducible representations for arbitrary q: we classify the continuous spectrum of the unitarity locus. We also recover some known results in the classical limit $q \rightarrow 1$ that were obtained by different means. Finally, we provide several explicit examples of signature characters.