QED In External Field Research Articles

Lightfront QED and Intense Field Physics

We briefly review the particular relevance of lightfront quantisation to QED in external fields modelling intense lasers.

QED in external fields: A functional point of view

A functional partial differential equation is set for the proper graphs generating functional of QED in external electromagnetic fields. This equation leads to the evolution of the proper graphs with the external field amplitude and the external field gauge dependence of the complete fermion propagator and vertex is derived non-perturbativally.

QED in external field with space–time uniform invariants: Exact solutions

We study exact solutions of Dirac and Klein–Gordon equations and Green functions in d-dimensional QED and in an external electromagnetic field with constant and homogeneous field invariants. The cases of even and odd dimensions are considered separately; they are essentially different. We direct attention to the asymmetry of the quasienergy spectrum, which appears in odd dimensions. The in and out classification of the exact solutions as well as the completeness and orthogonality relations is strictly proven. Different Green functions in the form of sums over the exact solutions are constructed. The Fock–Schwinger proper time integral representations of these Green functions are found. As physical applications, we consider the calculations of different quantum effects related to the vacuum instability in the external field. For example, we present mean values of particles created from the vacuum, the probability of the vacuum remaining a vacuum, the effective action, and the expectation values of the current and energy-momentum tensor.

On the string-inspired approach to QED in external field

Strassler's formulation of the string-derived Bern-Kosower formalism is extended to consider QED processes in homogeneous constant external field. A compact expression for the contribution of the one-loop with arbitrary number of external photon lines is given for scalar QED. Extension to spinor QED is shortly discussed.

Integral characteristics of radiation in QED in external field

New representations of the total probability of radiation and of the radiative energy loss for charged particle moving in an arbitrary extenal field are obtained in the frame of the quasiclassical operator approach in the quantum electrodynamics. From general results new representations of the total probability and the total intensity of the magnetic bremsstrahlung are derived. The polarization of the radiation, radiation of polarized electrons and radiative polarization have been considered as well.