Statistical particle-hole symmetry and the quantized Hall state at ν=5/2

In the absence of Landau level mixing, the half-filled Landau level possesses particle-hole symmetry which is spontaneously broken by the Pfaffian/anti-Pfaffian topological orders, which appear to be favored in numerical studies of the ν=5/2 quantum Hall state. Here we investigate the effect of quenched disorder on the nature of the ν=5/2 fractional quantum Hall state and compare our results with recent experimental measurement of thermal Hall effect at ν=5/2.