VARIATIONAL SOLUTION OF A SUPERFLUIDITY MODEL

We derive, using the variational principle for the free energy, the so lution of a model for superfluidity proposed in a previous paper. The solution has the phase diagram and the excitation spectrum expected fr om a superfluid. We draw the attention to the face that the model is o btained, as compared with the Bogoliubov model, by a milder suppressin g of interactions with the zero mode fluctuations, leading to the good spectral properties of superfluidity.