How a Single Photon Can Act Like Many Photons
Matin Hallaji, Amir Feizpour, Greg Dmochowski, Josiah Sinclair, Aephraim M. Steinberg · 2015
The weak nonlinear effect of a single photon on a probe beam is amplified by postselecting on a rare final state ("WVA" effect). The resulting cross-phase shift is up to five times greater than the usual single-photon phase shift.