Low-frequency response of a collectively pinned vortex manifold

A low-frequency dynamic response of a vortex manifold in a type-II superconductor can be associated with thermally activated tunneling of large portions of the manifold between pairs of metastable states. We suggest that statistical properties of these states can be verified by using the same approach for the analysis of thermal fluctuations the behavior of which is well known. The exponent describing the frequency dependence of a linear response is found for the generic case of a vortex manifold with nondispersive elastic moduli and also for the case of thin superconducting film in which the compressibility modulus is always nonlocal.