Dokument: Strong-field Breit-Wheeler pair production in short laser pulses
| Titel: | Strong-field Breit-Wheeler pair production in short laser pulses | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=41295 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20170223-105827-7 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Jansen, Martin [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Dr. Müller, Carsten [Gutachter] Prof. Dr. Egger, Reinhold [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 530 Physik | |||||||
| Beschreibung: | The current progress in high-intensity laser technology provides experimental access to unprecedented high field strengths and thus allows to explore the interaction between light and matter in new regimes. Presently emerging facilities, like the Extreme Light Infrastructure, offer prospects to probe scenarios where the theory of quantum electrodynamics (QED) predicts the occurrence of novel effects. Despite being one of the best established physical theories today, QED is still awaiting systematic experimental verification in time-dependent fields of high strength. This could be achieved by dedicated experiments aiming at a variety of strong-field phenomena, like the Breit-Wheeler process.
Predicted by Breit and Wheeler in 1934, the collision of two energetic photons can lead to the creation of an electron-positron pair. Early theoretical studies have shown that upon application of a coherent light source, the strong-field Breit-Wheeler (SFBW) process can be induced as a multiphoton reaction. In these studies, the laser field was treated as an infinitely extended plane wave. However, employing modern high-intensity lasers, the highest intensities are reached in very short pulses, comprising only few optical cycles. Therefore, the question arises to which extent the process is affected by the properties of the laser field, in particular by the finite duration and the spectral composition. In this thesis, we study the SFBW process in short laser pulses and acquire answers to these questions. Our approach is based on detailed S-matrix calculations in the framework of laser-dressed QED, allowing us to obtain numerical predictions for the process probability in various parameter constellations. The analysis of the corresponding results has given rise to general insights about the process, which shall be presented in detail. In particular, a new quantitative model for multiphoton processes in short laser pulses is developed, which clearly reveals and explains the connection between the properties of the laser field and the energy spectrum of the produced particles. Moreover, focusing on the quantum nature of the process, the relevance of interferences shall be investigated. Following the multiphoton approach, distinct interference effects arising in the particle spectra can be detected and understood, revealing a characteristic dependence on the carrier-envelope phase of the laser pulse. Besides, further expanding our model approach allows us to examine general properties of multiphoton-interference processes driven by pulsed laser fields with a continuous frequency spectrum. In addition, the influence of the particle's spin on the SFBW process is inspected by way of comparison between predictions from full Dirac theory and scalar theory, respectively. Facilitating a simplified theoretical treatment, the scalar case can be regarded as an approximation to the Dirac case. Our study examines various regimes and includes an intuitive approach to the underlying principle. This way, we also gain information on the applicability of the spinless approximation. Finally, we regard an extended scenario involving a second laser pulse which arrives with a variable delay. The contributions from both pulses to the pair-creation process induce pronounced interference effects, which are intrinsically different to the multiphoton interferences. Inspecting the influence of the delay time, further fundamental properties of the SFBW process can be analyzed and understood from a complementary perspective. The present study enhances the understanding of several aspects inherent to the SFBW process. Furthermore, some of our concepts and insights can be applied to other strong-field phenomena, such as nonlinear Compton scattering, as well. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Physik » Theoretische Physik | |||||||
| Dokument erstellt am: | 23.02.2017 | |||||||
| Dateien geändert am: | 23.02.2017 | |||||||
| Promotionsantrag am: | 12.01.2017 | |||||||
| Datum der Promotion: | 10.02.2017 |
