Euclidean mirrors: enhanced vacuum decay from reflected instantons

Understand

We study the tunneling of virtual matter-antimatter pairs from the quantum vacuum in the presence of a spatially uniform, time-dependent electric background composed of a strong, slow field superimposed with a weak, rapid field.

• After analytic continuation to Euclidean spacetime, we obtain from the instanton equations two critical points.
• While one of them is the closing point of the instanton path, the other serves as an Euclidean mirror which reflects and squeezes the instanton.
• It is this reflection and shrinking which is responsible for an enormous enhancement of the vacuum pair production rate.