The nematic phase of a system of long hard rods

by Alessandro Giuliani (Università di Roma 3)

Tuesday 13 Mar 2012, 16:00 → 18:00 Europe/Rome

Aula Conversi (Dipartimento di Fisica - Ed. G. Marconi)

In this seminar, I will consider a two-dimensional lattice model for liquid crystals consisting of long rods interacting via purely hard core interactions, with two allowed orientations defined by the underlying lattice. I will present a rigorous proof of the existence of a nematic phase: more precisely, I will show that at intermediate densities the system exhibits orientational order, either horizontal or vertical, but no positional order. The proof is based on a two-scales cluster expansion: first the system is coare-grained on a scale comparable with the rods' length; then the resulting effective theory is re-expressed as a contour's model, which can be treated by Pirogov-Sinai methods. Joint work with M. Disertori.