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A: Fachverband Atomphysik

A 21: Interaction with Strong or Short Laser Pulses II

A 21.1: Fachvortrag

Wednesday, March 4, 2009, 16:30–17:00, VMP 6 HS-C

Spin effects in purely laser-induced pair creation — •Matthias Ruf, Carsten Müller, Karen Z. Hatsagortsyan, Guido R. Mocken, and Christoph H. Keitel — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg

Electron-positron pair creation is investigated in an oscillating electric field, which can be formed by two counter-propagating laser fields. A numerical ansatz is employed to propagate the corresponding Dirac equation on a 2+1 dimensional space-time grid. This enables us to obtain the momentum distribution of the created particles in a single computation. It is found that for linear laser polarization the spin state of the electron is not relevant for the process, whereas for circular polarization a strong asymmetry occurs between the two spin orientations. This effect can be explained in the context of a quasi-classical approach by an additional spin term of the classical Hamiltonian. The process is in principle of interest for experimental studies in upcoming intense x-ray laser facilities.