What does the Modular Group Have to do With Materials?

SPECIAL GEOMETRY OF MATERIALS SEMINAR
Topic:What does the Modular Group Have to do With Materials?
Speaker:Robert MacPherson
Affiliation:Hermann Weyl Professor, Institute for Advanced Study
Date:Friday, November 20
Time/Room:4:00pm - 5:00pm/S-101

Simple cell decompositions of surfaces are in one to one correspondence with certain conjugacy classes of subgroups of the modular group. Polycrystalline structures in 2 dimensional materials give rise to statistical simple cell decompositions of the plane, and therefore to statistical subgroups of the modular group. Can the structural properties of the modular group help to illuminate the properties of polycrystalline materials?