We report a theoretical analysis of the half-polarized quantum Hall states
observed in a recent experiment. Our numerical results indicate that the ground
state energy of the quantum Hall ν=2/3 and ν=2/5 states versus spin
polarization has a downward cusp at half the maximal spin polarization. We map
the two-component fermion system onto a system of excitons and describe the
ground state as a liquid state of excitons with non-zero values of exciton
angular momentum.Comment: 4 pages (RevTeX), 3 figures (PostScript), added reference