Wigner function approach to single electron coherence in quantum Hall edge channels

Recent electron quantum optics experiments performed with on-demand single electron sources call for a mixed time/frequency approach to electronic quantum coherence. Here, we present a Wigner function representation of first-order electronic coherence and show that it provides a natural visualization of the excitations emitted by recently demonstrated single electron sources. It also gives a unified perspective on single particle and two particle interferometry experiments. In particular, we introduce a nonclassicality criterion for single electron coherence and discuss it in the context of Mach-Zehnder interferometry. Finally, the electronic Hanbury Brown and Twiss and the Hong-Ou-Mandel experiments are interpreted in terms of overlap of Wigner function, thus connecting them to signal processing.