Pairing of composite electrons and composite holes in νT = 1 quantum Hall bilayers

Motivated by recent experimental indications of preformed electron-hole pairs in nu(T) = 1 quantum Hall bilayers at relatively large separation, we formulate a Chern-Simons (CS) theory of the coupled composite electron liquid (CEL) and composite hole liquid (CHL). We show that the effective action of the CS gauge field fluctuations around the saddle point leads to stable pairing between CEL and CHL. We find that the CEL-CHL pairing theory leads to a dominant s-wave channel in contrast to the dominant p-wave channel found in the CEL-CEL pairing theory. Moreover, the CEL-CHL pairing is generally stronger than the CEL-CEL pairing across the whole frequency spectrum. Finally, we discuss possible differences between the two pairing mechanisms that may be probed in experiments.