Dynamically assisted Sauter-Schwinger effect in inhomogeneous electric fields

Via the world-line instanton method, we study electron-positron pair creation by a strong (but sub-critical) electric field of the profile e/ cosh2(kx) superimposed by a weaker pulse e ′ / cosh2(ωt). if the temporal keldysh parameter γ ω = mω/(qe) exceeds a threshold value γ crit which depends on the spatial keldysh parameter γ k = mk/(qe), we find a drastic enhancement of the pair creation probability — reporting on what we believe to be the first analytic non-perturbative result for the interplay between temporal and spatial field dependences e(t, x) in the sauter-schwinger effect. finally, we speculate whether an analogous effect (drastic enhancement of tunneling probability) could occur in other scenarios such as stimulated nuclear decay, for example.