Edge excitations of the ν= spin-singlet quantum Hall state

The spectrum of edge excitations is derived for the spin unpolarized {ν}=2 and {ν}=2/3 fractional quantum Hall effect (FQHE). Numerical diagonalization of a system of six electrons on a disk confirms that the edge {ν}=2/3 spin-singlet FQHE state consists of oppositely directed spin and charge branches on the same physical edge. The highly correlated {ν}=2/3 singlet edge is shown to have the same spin branch as the {ν}=2 singlet edge, providing evidence that the same SU(2)ₖ₌₁ Kac-Moody algebra describes all unmixed spin branches. The spin and charge branches of the singlet state at {ν}=2/3 are less coupled than the two branches of the spin polarized state at the same filling factor, suggesting that the conductance along an edge may increase sharply across the polarized unpolarized transition.