Scaling approach to pinning: Charge density waves and giant flux creep in superconductors

A general scaling approach to pinning and response in weakly disordered systems is developed that considers pinning at arbitrary high energy barriers. These are a consequence of a disordered T=0 renormalization-group fixed point which characterizes the condensed phase. Application to flux creep in superconductors yields a creep velocity (j) -Cj^- where is related to the roughness exponents of the flux-line lattice. We argue that =0 (log) and = (d-2) /2 as for charge-density waves.