Analytical computations of multi-loop scattering amplitudes

SNIC 2018/3-470


SNIC Medium Compute

Principal Investigator:

Henrik Johansson


Uppsala universitet

Start Date:


End Date:


Primary Classification:

10301: Subatomic Physics

Secondary Classification:

10305: Astronomy, Astrophysics and Cosmology



With the development of modern analytical methods for the computation of scattering amplitudes in quantum field theory and string theory, such as generalized unitarity, on-shell recursion, color-kinematics duality and the double-copy prescription, higher-order terms in the perturbative expansion of gauge and gravity theories have become increasingly accessible. The research group, within the Division of Theoretical Physics, studies the detailed structure of these amplitudes in various (supersymmetric) theories, and develops new methods and technologies for efficient computations thereof. Central research goals in this program includes: a better understanding of the underlying mathematical structure of scattering amplitudes and of their physical behavior in the ultraviolet regime; the latter is crucial for identifying well-behaved theories that are candidates for describing a consistent theory of quantum gravity. Current on-going calculations in this direction include the detailed study of various supergravity theories at the two-loop order, and conformal gravity up to one loop order. More recently there have been efforts to use the accumulated knowledge from the amplitudes field to study binary black-hole inspirals and the emission of gravitational waves, which is of direct relevance to the LIGO and VIRGO experiments. Our research group aims at contributing to these efforts through direct higher-order calculations of effective potentials and gravitational radiation. The computations planned for this project are chiefly of analytic nature and will yield exact results at fixed orders in the perturbative loop expansion. The technical challenges involved are expected to be dominated by the analytic complexity of individual expressions (loop diagrams), and the number of such expressions that are to be considered in parallel.