Bethe Ansatz and Rogers-Ramanujan-type identities

Abstract

The Rogers-Ramanujan identity for ${}_1{\psi }_1$ $$\sum _{n\in \mathbb{Z}}\frac{(a;q{)}_n}{(b;q{)}_n}{z}^n=\frac{(q,b/a,az,q/az;q{)}_{\infty }}{(b,q/a,z,b/az;q{)}_{\infty }}$$ can be classified as one related to the Bethe Ansatz for ``chain length $N=1$, ground state XXZ model with an arbitrary negative spin''.