Pair production via crossed lasers - art. no. 125001

We discuss the intrinsically nonperturbative probability P-0 for electron-p ositron production in the overlap region of a pair of high-intensity lasers , by adapting the Fradkin representation for the logarithm of the fermion d eterminant to several models defined as approximations to the exact problem . In each case we find for P-0 an expression resembling Schwinger's 1951 ex pression for the vacuum persistence probability of pair production in an ex ternal electric field, proportional to an exponential factor that contains an essential singularity, and hence does not admit a perturbative expansion about zero coupling. Qualitative estimates of the best of these models sug gest that realistic yields for e(+)e(-) production must await lasers of int ensity 10(29) W/m(2), roughly seven orders of magnitude more powerful than the highest intensity of currently known lasers. We comment on the possibil ity of producing a quark-antiquark pair in this way, and note the possibili ty of achieving temporary, but large separations of the produced q-(q) over bar.