Novel Families of Fractional Quantum Hall States: Pairing of Composite Fermions

Fractional quantum Hall (FQH) states have recently been observed at unexpected values of the filling factor nu. Here we interpret these states as a novel family of FQH states involving pairing correlations rather than Laughlin correlations among the quasiparticles (QP's). The correlations depend upon the behavior of the QP-QP pseudopotential V_QP(L'), the interaction energy of a pair as a function of the pair angular momentum L'. This behavior, known from numerical studies of small systems, is used to demonstrate that pairing correlations give rise to FQH states at the experimentally observed values of nu.