Theory of suppressed shot noise at ν = 2/(2p ± 1)

We study the edge states of fractional quantum Hall liquid at bulk filling factor ν = 2/(2p + _χ) with p being an even integer and _χ = ±1. We describe the transition from a conductance plateau G = νG₀ = νe²/h to another plateau G = G₀/(p + _χ) in terms of chiral Tomonaga-Luttinger liquid theory. It is found that the fractional charge q which appears in the classical shot noise formula S_I = 2q<I_b> is q = e/(2p + _χ) on the conductance plateau at G = νG₀ whereas on the plateau at G = G₀/(p + _χ) it is given by q = e/(p + _χ). For p = 2 and _χ = -1 an alternative hierarchy construction is also discussed to explain the suppressed shot noise experiment at bulk filling factor ν = 2/3.