Topological Glass Transition in Entangled Flux State

We predict a glass transition in the recently discovered flux-fiuid state of high-T, superconductors due to topological entanglements. Two possible relaxation mechanisms are considered — single-flux-line motion with relaxation time t -exp[exp[(A/d) ][, and collective motion of many flux lines with relaxa-tion time r " -exp[(A/d) 1, where A is the magnitude of transverse fluctuations of flux lines and d is the intervortex spacing. This extremely slow relaxation enables the system of entangled flux lines to support supercurrents in the presence of only a few strong pinning centers.