Many-body coherence effects in conduction through a quantum dot in the fractional quantum Hall regime

We study a quantum dot in the fractional quantum Hall regime by solving the problem exactly for up to eight electrons at filling factors between 1 and 1/3. Many-body coherence in the fractional regime strongly suppresses the resonant conductance through a weakly coupled dot below the integer regime values. In particular, using the edge-wave theory of excitations, we predict that, at low temperatures and small bias voltages, all conductance peaks are lowered by a factor of 1/N at ν=1/3, and that at ν=2/3 odd and even peaks are suppressed differently. We also show that strongly coupled excited states lead to an anomalous temperature dependence of the resonance peaks, whereas weakly coupled excited states can be identified from the line shapes in nonlinear measurements.