Incompressible quantum Hall states

Considering each electron as a superposition of fictitious fractionally charged particles allows, with the help of a natural ansatz, a systematic identification and characterization of the incompressible quantum Hall states at noninteger filling factors. Explicit Laughlin-type wave functions are obtained for all the incompressible states and their quasiparticles. The order of stability of the various states predicted on the basis of physically plausible rules is in agreement with experiments. Although in principle all rational fractions are observable, these rules imply that the even-denominator fractions are in general much less stable than the odd-denominator ones.