In this work, we make use of the worldline formalism, and in concrete, the R representation, a new one that manifests the gauge invariant in the amplitude focus on the scalar QED to obtain the scattering at tree level, ...

In this study we use the worldline formalism to sum up all ladders and cross-ladders in the '2_ theory with zero mass of the _ particle.

The phenomenon of light has been studied for many years, from Compton scattering to light-by-light scattering in Quantum Field Theory. In the standard QFT formalism, with the use of Feynman’s rules, we can calculate several ...

Feynman grams (eg not to be regularized; a single integral represents all permutations of diagrams). After the brief introduction on the development of amplitudes of the photons begins the work of the thesis, where some ...

Using worldline numerics we are able of generate paths with Gaussian distribution to numerically approximate the propagator of arbitrary potentials. In particular, we focus on the study of nonrelativistic quantum bound ...

In this thesis we developed the world line formalism as a very efficient tool for calculating the effective action in the Einstein-Maxwell theory due to a scalar or spinor loop. The calculation is performed in the limit ...

The main objective of this thesis is to calculate some contributions in quantum electrodynamics QED (QED is a theory that describes the electromagnetic coupling of a charged particle to a quantum field.) for the effective ...

En esta tesis haciendo uso de la estructura asintótica del espaciotiempo y del formalismo de Newman-Penrose definimos la noción de centro de masa y spin para sistemas gravitacionales que emiten radiación gravitacional y ...