On the transfer matrix of the supersymmetric eight-vertex model. I. Periodic boundary conditions
Christian Hagendorf, Jean Liénardy
Abstract The square-lattice eight-vertex model with vertex weights a , b , c , d obeying the relation ( a 2 + a b ) ( b 2 + a b ) = ( c 2 + a b ) ( d 2 + a b ) and periodic boundary conditions is considered. It is shown that the transfer matrix of the model for L = 2 n + 1 vertical lines and periodic boundary conditions along the horizontal direction possesses the doubly degenerate eigenvalue Θ n = ( a + b ) 2 n + 1 . This proves a conjecture by Stroganov from 2001. The proof uses the supersymmetry of a related XYZ spin-chain Hamiltonian. The eigenstates of the transfer matrix corresponding to Θ n are shown to be the ground states of the spin-chain Hamiltonian. Moreover, for positive vertex weights Θ n is the largest eigenvalue of the transfer matrix.
arXiv:1711.04397•Journal of Statistical Mechanics Theory and Experiment•Mar 1, 2018•6 citations