Superfluidity and Superconductivity in Double-Layered Quantum Hall state

We discuss and review the basic physics that leads to superfluidity/superconductivity in certain quantum Hall states, in particular the so-called double-layered (mmm) state. In the K-matrix description of the quantum correlation in quantum Hall states, those states with det(K)=0 contain a special correlation that leads to superfluidity/superconductivity. We propose a four-terminal measurement to test the DC Josephson-like effect in interlayer tunneling, so that the superfluidity/superconductivity in the (mmm) states can be settled experimentally.