Analysis of a SU(4) generalization of Halperin's wave function as an approach towards a SU(4) fractional quantum Hall effect in graphene sheets

Inspired by the fourfold spin-valley symmetry of relativistic electrons in graphene, we investigate a possible SU(4) fractional quantum Hall effect, which may also arise in bilayer semiconductor quantum Hall systems with small Zeeman gap. SU(4) generalizations of Halperin's wave functions [Helv. Phys. Acta 56, 75 (1983)], which may break differently the original SU(4) symmetry, are studied analytically and compared, at nu=2/3, to exact-diagonalization studies.