  We consider a sequence of quantized Lorentzian pulses of non-interacting
electrons impinging on a quantum point contact (QPC) and study the waiting time
distribution (WTD), for any transmission and any number of pulses. As the
degree of overlap between the electronic wave functions is tuned, the WTD
reveals how the correlations between particles are modified. In the weak
overlap regime, the WTD is made of several equidistant peaks, separated by the
same period as the incoming pulses, contained in an almost exponentially
decaying envelope. In the other limit, the WTD of a single quantum channel
subjected to a constant voltage is recovered. In both cases, the WTD stresses
the difference between the fluctuations induced by the scatterer and the ones
encoded in the incoming quantum state. A clear cross-over between these two
situations is studied with numerical and analytical calculations based on
scattering theory.
