Dynamic scaling and spontaneous symmetry breaking at the gel point

The gel point is a continuous transition between fluid and solid states, and therefore exhibits a variety of scaling laws for the linear viscoelastic behavior. These are derived, together with a scaling law for the nonlinear shear relaxation modulus and a sum rule, valid in both fluid and solid states, which has a counterpart in superconductivity. Our results are generic consequences of both dynamic critical phenomena and spontaneous symmetry breaking, and therefore are not equivalent to some previous predictions, based on an analogy with percolation.