On the nonextensivity of entropy of the weakly interacting Bose systems

In present paper we apply the quantum field theory of thermodynamics to treat boson systems. We describe the physical behaviour of Bose systems and discuss the Bose condensation close to the equilibrium in a simple case. We make an attempt to deform the Bose distribution a little bit – which may mean a weak interaction inside the system – and we examine the consequences of it, especially the change of critical temperature and the nonextensive of entropy.