Title: Nematic phase transitions in two-dimensional systems
Author(s):

	B.Berche (Groupe M, Laboratoire de Physique des Matériaux, UMR CNRS 7556, Université Henri Poincaré, Nancy 1, F-54506 Vandœuvre les Nancy Cedex, France; Centro de Física, Instituto Venezolano de Investigaciones Científicas, Apartado 21827, Caracas 1020A, Venezuela) ,
	R.Paredes (Centro de Física, Instituto Venezolano de Investigaciones Científicas, Apartado 21827, Caracas 1020A, Venezuela) ,

Simulations of nematic-isotropic transition of liquid crystals in two dimensions are performed using an O(2) vector model characterized by non linear nearest neighbour spin interaction governed by the fourth Legendre polynomial P₄. The system is studied through standard Finite-Size Scaling and conformal rescaling of density profiles or correlation functions. The low temperature limit is discussed in the spin wave approximation and confirms the numerical results, while the value of the correlation function exponent at the deconfining transition seems controversial.

Key words: liquid crystal, orientational transition, nematic phase, topological transition
PACS: 05.40.+j, 64.60.Fr, 75.10.Hk