Antibunching of distorted optical wave packets at a beam splitter
  Interference of single-photon wave packets at a beam splitter usually leads to an anticorrelation of the light intensity in the two output ports of the beam splitter. The effect may be regarded as ``bunching'' of the photons at the beam splitter and has widely been interpreted as a result of quantum mechanical interference between the probability amplitudes of indistinguishable bosonic particles. Here we show that when the wave packets are sufficiently distorted, then the opposite behaviour is observed, i.e., simultaneous clicks of the photodetectors in the two output ports are favoured, which may be regarded as ``antibunching'' of the photons at the beam splitter. 
T. Gruner and D.-G. Welsch (FSU Jena)