New phenomena at high intensities

Quantum electrodynamics is the fundamental theory of electrons, positrons and photons.

It is well tested at low intensities, but high-intensity electromagnetic fields lead to new phenomena and a largely experimentally uncharted territory.

The development of high-intensity lasers promises fields with unprecedented intensities, which can be used to gain new insights into fundamental physics.

The technique used to generate these lasers was recently awarded the Nobel Prize, and is also motivated by practical applications. Calculations for nonlinear/nonperturbative processes in strong fields are often challenging.

We have developed new methods that allow us to calculate for the first time parts of processes that were neglected for several decades. We find that the neglected parts are in general as important as parts that were previously calculated.

We will apply our methods to other processes and to provide results that can be tested in experiments planned for the next couple of years. Several particles can be produced by a single particle colliding with a laser. We will develop new methods for studying such processes in cases where existing methods break down.

In some cases one can treat the field as locally constant, but this approximation breaks down for particles with low or high energy or for the ``moderately´´ high intensities planned for the first new experiments. We will develop new methods for taking more realistic field shapes into account.