Discrete symplectic fermions on double dimers and their Virasoro representation
David Adame-Carrillo
TL;DR
This work constructs a rigorous lattice realization of the logarithmic CFT of symplectic fermions with central charge $c=-2$ on the square lattice via the double-dimer model. It develops a discrete holomorphic fermion framework, connects correlation functions to Grassmann/Wick formalisms, and shows that the space of local fields on $oldsymbol{Z}^2$ carries a Virasoro representation obtained through a Sugawara construction on current modes. The analysis spans finite temperleyan domains and their thermodynamic limit, identifying the two-point function with the derivative of the full-plane Green’s function and establishing multipoint correlators by Wick’s theorem. The main result is a fully discrete Virasoro action at the lattice level, providing a concrete bridge between lattice dimer models and logarithmic CFT structures with $c=-2$.
Abstract
A discrete version of the Conformal Field Theory of symplectic fermions is introduced and discussed. Specifically, discrete symplectic fermions are realised as holomorphic observables in the double-dimer model. Using techniques of discrete complex analysis, the space of local fields of discrete symplectic fermions on the square lattice is proven to carry a representation of the Virasoro algebra with central charge $-2$.
