Electron thermal, quantum, shot, and photo-assisted noise: From spectroscopy to current-current correlator in time domain

We have measured the current fluctuations emitted by a tunnel junction with a very wide bandwidth, from 0.3 to 13 GHz, down to very low temperature T = 35 mK. This allowed us to perform the spectroscopy (i.e., measure the frequency dependence) of thermal noise, shot noise and photo-assisted noise. Thanks to the very wide bandwidth of our measurement, we can deduce the current-current correlator in time domain. We observe the thermal decay of this correlator as well as its oscillations with a period h/eV, a direct consequence of the effect of the Pauli and Heisenberg principles in quantum electron transport.