Thursday, April 27, 2017, 16:00
OSGA/EG06
Antonino Di Piazza, Max-Planck-Institut Heidelberg, Germany
Abstract:
Classical electrodynamics (CED) and quantum electrodynamics (QED) are
well established physical theories and their predictions have been
confirmed experimentally in various regimes and with extremely high
accuracy.
However, there are still areas of CED and of QED that deserve theoretical and experimental investigation, especially when physical processes occur in the presence of strong background electromagnetic fields, i.e., of the order of the so-called "critical" field of QED [1]. In the presence of electromagnetic fields of such a high strength even the vacuum becomes unstable and electron-positron pair production spontaneously occurs. In view of the increasingly stronger available laser fields it is becoming feasible to employ them to test CED and QED under the extreme conditions supplied by intense fields [1].
After a broad introduction on CED and QED, I describe different regimes of laser-matter interaction at ultra-high laser intensities and introduce present and upcoming experimental efforts to test the two theories under such extreme conditions. As a prominent theoretical example of open problems which can be addressed also experimentally, I focus on the so-called "radiation reaction" problem both classically [2] and quantum mechanically [3]. After showing that in the full quantum regime the problem of radiation reaction is intrinsically multiparticle, I point out the relation of this problem with the development of the so-called electron-positron-photon QED cascades in the collision of two strong laser beams [4]. Finally, I describe recent experimental results on the laser-based generation of high-energy, collimated positron [5] and electron-positron [6] beams and their relevance for astrophysics.
[1] A. Di Piazza, C. Müller, K. Z. Hatsagortsyan, and C. H. Keitel, Rev. Mod. Phys. 84, 1177 (2012).
[2] A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel, Phys. Rev. Lett. 102, 254802 (2009).
[3] A. Di Piazza, K. Z. Hatsagortsyan, and C. H. Keitel, Phys. Rev. Lett. 105, 220403 (2010); N. Neitz and A. Di Piazza, Phys. Rev. Lett. 111, 054802 (2013).
[4] M. Tamburini, A. Di Piazza, and C. H. Keitel, arXiv:1511.03987.
[5] G. Sarri et al., Phys. Rev. Lett. 110, 255002 (2013).
[6] G. Sarri et al., Nature Commun. 6, 6747 (2015).