How to access QED at a supercritical Coulomb field
How to access QED at a supercritical Coulomb field
In slow collisions of two bare nuclei with the total charge number larger than the critical value, ${Z}_{\mathrm{cr}}\ensuremath{\approx}173$, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. Detection of the spontaneous emission of positrons would be the direct evidence of this fundamental phenomenon. However, the …