Ulm 2004 – wissenschaftliches Programm

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MP: Theoretische und Mathematische Grundlagen der Physik

MP 3: Strings und Quantentheorie in externen Feldern

MP 3.3: Fachvortrag

Dienstag, 16. März 2004, 14:50–15:15, H 22

Spontaneous Particle Creation within the External Field Approximation of QED — •Nikodem Szpak — Institut fuer Theoretische Physik, J.W.Goethe Universität Frankfurt, 60054 Frankfurt

Strong electrodynamic fields in QED may lead to destabilization of the vacuum. Physical intuition supported by non-rigorous calculations predict spontaneous particle creation from vacuum if the strength of the electric field exceeds some threshold. Rigorously, the question about the existence of the effect is still open, even at the level of model fields. We treat the problem within an external field approximation of QED, which is in common use for strong fields, and present conditions for its validity, which are not necessarily fulfilled by any strong field. The spontaneous particle creation, defined by the adiabatic limit, is studied analytically and numerically, first for a model electric field. The aim of the study is to provide a conclusive model, which applied to future experimental results – like collision of two heavy nuclei (like U⁹²⁺) – will help to decide the question about the existence of the effect.

We review the present state of the theory concerning spontaneous particle creation and report on the open theoretical problems.