Quantum disordering of the 111 state and the compressible-incompressible transition in quantum Hall bilayer systems

We systematically discuss properties of quantum disordered states of the quantum Hall bilayer at nu(T)=1. For one of them, the so-called vortex metal state, we find off-diagonal long-range order of algebraic kind, and derive its transport properties. It is shown that this state is relevant for the explanation of the "imperfect" superfluid behavior and persistent intercorrelations, for large distances between layers, that were found in experiments.