Paired Hall state at half filling

Abstract

The existence of a novel incompressible quantum liquid for spinless fermions at ν=1/2 in the Hall effect is suggested. This state is plausibly related by smooth extrapolation in quantum statistics to a strong p-wave pairing state of fermions in zero magnetic field, and reduces to a state previously proposed by Halperin in the (unrealistic) limit of tightly bound pairs. It supports unusual excitations, including neutral fermions and charge-e/4 anyons with statistical parameter θ=π/8. Numerical experiments are presented, which provide evidence for several aspects of our theory.