  Starting from a microscopic model of liquids, we construct an effective
theory of an overlap field through duplication of the system and
coarse-graining. We then propose a recipe to extract a relaxation time and two
characteristic length scales of a supercooled liquid from this effective field
theory. Appealing to the Ginzburg-Landau-Wilson paradigm near the putative
critical point, we further conclude that this effective field theory resides
within the Ising universality class.
