A c=-2 boundary changing operator for the Abelian sandpile

TL;DR

This paper identifies a boundary primary operator in the Abelian sandpile model that changes boundary conditions, linking it to a c=-2 logarithmic conformal field theory and expanding understanding of boundary effects.

Contribution

It introduces a specific boundary operator of weight -1/8 that effects boundary condition changes in the Abelian sandpile model, connecting it to logarithmic CFT.

Findings

The boundary changing operator has weight -1/8.

It belongs to a c=-2 logarithmic conformal field theory.

The operator mediates boundary condition transitions in the model.

Abstract

We consider the unoriented two-dimensional Abelian sandpile model on the half-plane with open and closed boundary conditions. We show that the operator effecting the change from closed to open, or from open to closed, is a boundary primary field of weight -1/8, belonging to a c=-2 logarithmic conformal field theory.