Regime Interpretation of Anomalous Vortex Dynamics in 2D Superconductors

Low-frequency dynamic impedance [σ^-1(ω,T)≡(σ₁+iσ₂)^-1] measurements on Josephson junction arrays found that σ₁~|lnω|, σ₂~const. This implies anomalously sluggish vortex mobilities μV(ω)~σ₁^-1, and is in conflict with general dynamical scaling expressions. We calculate (a) σ(ω,T) by real-space vortex scaling and (b) μV(ω) using Mori's formalism for a screened Coulomb gas. We find, in addition to the usual critical (large-{ω}) and hydrodynamic (low-{ω}) regimes, a new intermediate-frequency scaling regime into which the experimental data fall. This resolves the above mentioned conflict and makes explicit predictions for the scaling form of σ(ω,T).