Bilayer paired quantum Hall states and Coulomb drag

We consider a number of strongly correlated quantum Hall states that are likely to be realized in bilayer quantum Hall systems at total Landau level filling fraction nu (p), = 1. One state, the (3,3,-1) state, can occur as an instability of a compressible state in the large dll(B) limit, where d and l(B) are the interlayer distance and magnetic length, respectively. This state has: a hierarchical descendent that is interlayer coherent. Another interlayer coherent state, which is expected in the small dll(B) limit is the well-known Halperin (1,1,1) state. Using the concept of composite fermion pairing, we discuss the wave functions that describe these states. We construct a phase diagram using the Chern-Simons Landau-Ginzburg theory and discuss the transitions between the various phases. We propose that the longitudinal and Hall-drag resistivities can be used together with interlayer tunneling to experimentally distinguish these different quantum Hall states. Out work indicates the bilayer nu (T) = 1 quantum Hall phase diagram to be considerably richer than that assumed so far in the literature.