  Identifying and controlling decoherence in single electron sources (SES) is
important for their applications in quantum information processing. The recent
experiments with ultrashort electron pulses [J. D. Fletcher et al., Nat.
Commun. 10, 5298 (2019)] demonstrate strong decoherence that cannot be caused
by traditional mechanisms such as electron-electron or electron-phonon
interactions. Here we propose timing noise as a universal model, consistent
with existing experimental data, to explain strong decoherence of ultrafast SES
pulses, without resorting to any specific microscopic mechanism for such
decoherence. We also propose a protocol to filter out timing noise which works
even in the presence of other decoherence effects, such as those present in,
e.g., low-energy SESs.
