The University of Michigan Combinatorics Seminar
Fall 2006
November 17, 4:10-5:00, 3866 East Hall

The emergence of the electrostatic field as a
Feynman sum in random tilings with holes

Mihai Ciucu

Georgia Institute of Technology


We consider random lozenge tilings on the triangular lattice with holes Q_1,...,Q_n in some fixed positions. For each unit triangle not in a hole, consider the average orientation of the lozenge covering it. We show that the scaling limit of this discrete field is the electrostatic field obtained when regarding each hole Q_i as an electrical charge of magnitude equal to the difference between the number of unit triangles of the two different orientations inside Q_i. This is then restated in terms of random surfaces, yielding the result that the average over surfaces with prescribed heights at the union of the boundaries of the holes is, in the scaling limit, a sum of helicoids.