Moving Glass Phase of Driven Lattices

We study periodic lattices, such as vortex lattices, driven by an external force in a random pinning potential. We show that effects of static disorder persist even at large velocity. It results in a novel moving glass state which has analogies with the static Bragg glass. The lattice flows through well-defined, elastically coupled, static channels. We predict barriers to transverse motion resulting in finite transverse critical current. Experimental tests of the theory are proposed.