An exactly solvable quantum version of the classical dynamical system
characterised by the Hamiltonian H = lambda n Sigma(j=1)(n) p(j) + mu
Sigma(j,k=1)(n) (p(j)p(k))(1/2) cos(q(j) - q(k)) si presented. The eig
enfunctions and eigenvalues of the quantum system with periodic bounda
ry conditions are obtained in closed form.