Cancellation of divergences up to three loops in exceptional field theory

Loops in exceptional field theory

Feynman diagrams to three loops in three dimensional field theory

The two point integrals contributing to the self energy of a particle in a three dimensional quantum field theory are calculated to two loop order in perturbation theory as well as the vacuum ones contributing to the effective potential to three loop order. For almost every integral an expression in terms of elementary and dilogarithm functions is obtained. For two integrals, the master integra...

Screened Perturbation Theory to Three Loops

The thermal physics of a massless scalar field with a φ interaction is studied within screened perturbation theory (SPT). In this method the perturbative expansion is reorganized by adding and subtracting a mass term in the lagrangian. We consider several different mass prescriptions that generalize the one-loop gap equation to two-loop order. We calculate the pressure and entropy to three-loop...

Cancellation of Infrared Divergences in Thermal Qed

As a preliminary step, the radiation produced by a classical charged current coupled to a quantized Aμ is solved. To each order in α, all infrared divergences cancel between the virtual γ’s and the real γ’s absorbed from the plasma or emitted into the plasma. When all orders of perturbation theory are summed, the finite answer predicts a suppression of radiation with ω < αT . The analysis of QE...

The lattice ghost propagator in Landau gauge up to three loops using Numerical Stochastic Perturbation Theory

We complete our high-accuracy studies of the lattice ghost propagator in Landau gauge in Numerical Stochastic Perturbation Theory up to three loops. We present a systematic strategy which allows to extract with sufficient precision the non-logarithmic parts of logarithmically divergent quantities as a function of the propagator momentum squared in the infinite-volume and a → 0 limits. We find a...