Hong-Ou-Mandel experiment in a graphene interferometer*

The Hong Ou Mandel experiment, a two-particle interference effect, probes the indistinguishability and the quantum statistics of particles. It relies on the exchange amplitude phase which is 0 for bosons, π for fermions and any intermediate statistical phase for anyons. However, probing the quantum statistics demands synchronized, coherent and indistinguishable excitations at the single electron-level. Graphene that shows a high degree of coherence at the single electron level is a very promising material for two-particle interference. In this study, we show that when two single electron excitations are sent on a graphene beam splitter the exchange effect leads to a two-particle interference effect that is detected in the zero-frequency current correlation. We then extend our work to the electronic Mach Zehnder where the two-particle interference is now both governed by the exchange amplitude term and the Aharonov Bohm phase. We demonstrate the possibility to encode the information into the orbital part of the two-particle wave-function and tune its phase while it is propagating enabling to compare the single particle coherence to the two-particle one. We finally perform the quantum tomography protocol. This works open the way to particles braiding or entanglement of electron flying quantum bits in graphene.