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-${\mathit{Cj}}^{\mathrm{-}\mathrm{\mu }}$ 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.