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 {ν}(j){∝}exp-Cj^-μ where {μ} is related to the roughness exponents {ζ} of the flux-line lattice. We argue that {ζ}=0(log) and {μ}=(d-2)/2 as for charge-density waves.