  We show experimentally that even when no bias voltage is applied to a quantum
conductor, the electronic quantum partition noise can be investigated using GHz
radiofrequency irradiation of a reservoir. Using a Quantum Point Contact
configuration as the ballistic conductor we are able to make an accurate
determination of the partition noise Fano factor resulting from the
photo-assisted shot noise. Applying both voltage bias and rf irradiation we are
able to make a definitive quantitative test of the scattering theory of
photo-assisted shot noise.
