Chronocyclic Wigner function of ultrafast time-frequency entangled parametric downconversion states

As of today, ultrafast waveguided parametric downconversion (PDC) sources are a well-established tool for the flexible generation of a large variety of quantum states. In the PDC process, the intrinsic broadband nature of the pump pulses gets translated into a rich spectral-temporal pulse-mode structure of the generated photon states [1]. This structure has already driven elaborate theoretical considerations, which aim for a complete understanding of the PDC process.