We describe paired quantum Hall states at filling fractions $\nu$, where $\nu^{ -1}$ is an integer, and present explicit wavefunctions for these states. Experiments are proposed to distinguish between paired states of singlet and triplet symmetry. It is argued from existing experimental data that the $\nu=1/2$ state observed in double layer quantum wells is a singlet and not a triplet paired state. In contrast, this state has been interpreted as a `3-3-1 state' which is a triplet paired state.
Categories: cond-mat