Hannover 2010 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 55: Poster II
Q 55.60: Poster
Donnerstag, 11. März 2010, 16:00–19:00, Lichthof
Barrier Control in Tunneling e+-e− Photoproduction — •Sebastian Meuren1, Antonino Di Piazza1, Erik Lötstedt1, Alexander I. Milstein1,2, and Christoph H. Keitel1 — 1Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany — 2Budker Institute of Nuclear Physics, 630090 Novosibirsk, Russia
QED predicts that in the collision of a strong laser field and a relativistic nucleus, tunneling electron-positron pair production occurs. This process can be described as the tunneling of an electron from the filled, negative-energy Dirac see to a positive-energy state, under the influence of the external laser and nuclear fields. Since the tunneling barrier is very large (around 1 MeV, corresponding to twice the electron rest energy), this process has never been observed experimentally. In [1] we proposed to add to the above setup a weak, high-frequency laser field with a photon energy in the nucleus rest frame close to the pair production threshold. The absorption of one photon from this laser field significantly reduces the barrier to be still tunneled by the electron to go to the positive levels. In this way one can lower the required intensity of the strong laser field to observe the process. Our calculations show that tunneling electron-positron pair production can in principle be observed in the proposed scheme with currently available laser technology.
[1] A. Di Piazza, E. Lötstedt, A. I. Milstein and C. H. Keitel, Phys. Rev. Lett. 103, 170403 (2009).