Finite frequency measurement of the third moment of current noise in a tunnel junction

We report the first measurment of the third moment of current noise (2(f)i(-2f)>) in a mesoscpic device in a fully quantum regime (hf>>eV,kT). This is achieved by using a tunnel junction in a dilution refrigator (T=10mK) in the microwave regime (f=5GHz). The contribution from feedback effects and correlations induced by environnmental noise are both accounted for quantitatively. The noise susceptibility, the response of the current statistics to a fluctuating voltage, is also measured and corresponds exactly to theoritical predictions.