Paul Fendley has recently found a 'parafermionic' way to diagonalize a simple solvable Hamiltonian associated with the chiral Potts model. Here we indicate how this method generalizes to the τ 2 model with open boundaries and make some comments.
It has been shown recently by Baxter that the τ2(tq) model with open boundary conditions can be solved by the "parafermionic" method of Fendley. In Baxter's paper there are several conjectures, which were formulated based on numerical short-chain calculations. Here we present the proof of two of them.
Many years ago Baxter introduced an inhomogeneous two-dimensional classical spin model, now called the τ2(t) model with free boundary conditions, and he specialized the resulting quantum spin-chain Hamiltonian in a special limit to a simple clock Hamiltonian. Recently, Fendley showed that this clock Hamiltonian can be expressed in terms of free "parafermions." Baxter followed this up by showing that this construction generalizes to the more general τ2(t) model, provided some conjectures hold. In this paper, we will compare the different notations and approaches enabling us to express the Hamiltonians in terms of projection operators as introduced by Fendley. By examining the properties of the raising operators, we are then able to prove the last unproven conjecture in Baxter's paper left in our previous paper. Thus the eigenvectors can all be written in terms of these raising operators.