Phase transition in an exactly solvable nonpolynomial model

In the framework of a three-dimensional exactly solvable model the thermodynamic properties of a system of Bose particles are investigated. It is shown that this system has a phase transition of the first kind. The latent heat of this transition and the discontinuity of the specific heat are calculated. The model can be used for an approximate description of a superconducting phase transition in quasi-one-dimensional systems or a transition such as melting in such systems.