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arXiv · 1912.11015

Approximating higher-order nonlinear QED processes with first-order building blocks

Victor Dinu·Greger Torgrimsson
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Abstract

Higher-order tree-level processes in strong laser fields, i.e. cascades, are in general extremely difficult to calculate, but in some regimes the dominant contribution comes from a sequence of first-order processes, i.e. nonlinear Compton scattering and nonlinear Breit-Wheeler pair production. At high intensity the field can be treated as locally constant, which is the basis for standard particle-in-cell codes. However, the locally-constant-field (LCF) approximation and these particle-in-cell codes cannot be used when the intensity is only moderately high, which is a regime that is experimentally relevant. We have shown that one can still use a sequence of first-order processes to estimate higher orders at moderate intensities provided the field is sufficiently long. An important aspect of our new "gluing" approach is the role of the spin/polarization of intermediate particles, which is more nontrivial compared to the LCF regime.

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Victor Dinu, Greger Torgrimsson. 2020-06-04. Approximating higher-order nonlinear QED processes with first-order building blocks. https://doi.org/10.1103/physrevd.102.016018

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