Schwinger Effect: Observed or Proven?

[wolram]

I am not a frequenter of this forum so please excuse me if my
question is old hat or common knowledge.
has the Schwinger effect been observed or proven.

 

[humanino]

I think it has not been observed yet.
On e^+e^- pair production by a focused laser pulse in vacuum
or more recently :
Pulsations of the electron-positron plasma in the field of optical lasers
Of course, it has often been argued that such an effect is not experimentally accessible. (for instance in Phys Rev D 2, 7, 1191 (Oct 1 1970), Itzykson and Brezin http://www-spires.slac.stanford.edu/spires/find/hep/www?rawcmd=FIND+KEY++1105264 )

 

[wolram]

Thanks humanino

 

[EL]

Not even photon-photon scattering, a phenomena arising from creation of virtual electron-positron pairs, has been detected.

At least I hope no one has yet, since I'm working on it right now...