Critical and off-critical studies of the Baxter-Wu model with general toroidal boundary conditions

The operator content of the Baxter-Wu model with general toroidal boundary conditions is calculated analytically and numerically. These calculations w ere done by relating the partition function of the model with the generatin g function of a site-colouring problem in a hexagonal lattice. Extending th e original Bethe-ansatz solution of the related colouring problem we are ab le to calculate the eigenspectra of both models by solving the associated B ethe-ansatz equations. We have also calculated, by exploring the conformal invariance at the critical point, the mass ratios of the underlying massive theory governing the Baxter-Wu model in the vicinity of its critical point .