Correlators of the phase model
  We introduce the phase model on a lattice and solve it using the algebraic Bethe ansatz. Time-dependent temperature correlation functions of phase operators and the "darkness formation probability" are calculated in the thermodynamical limit. These results can be used to construct integrable equations for the correlation functions and to calculate there asymptotics. 
N.M. Bogoliubov, A.G. Izergin, N.A. Kitanine