Scattering Amplitudes and Ambitwistor Strings

Research Group: 
Centre for Research in String Theory
Length of Study in Years: 
Full-time Project: 
Project Description: 
This project focuses on a new approach to describe quantum field theory, and in particular to calculate scattering amplitudes, which is inspired by string theory. A new and intriguing breed of “string-like” theories, known as ambitwistor strings, is actually a class of well-known particle theories in disguise, including gravity and gauge theory. While these theories are formulated as two-dimensional conformal field theories, similarly to string theory, they do not possess the infinite tower of massive states that characterises string theory, but possess only a massless spectrum perturbatively. My recent research has opened the way to make these theories a serious tool to calculate scattering amplitudes at loop level in theories of physical interest.

The major goal of the project will be to understand the nature and the applicability of ambitwistor strings. There are plenty of questions. How does the all-loop expansion work? What is the most general class of theories that these models can describe? How can we make the calculations more efficient? Beyond scattering amplitudes, what other quantities can we calculate? Can they bring a new light into the connections between theories, such as those between gauge theory and gravity? And how does standard string theory fit into this picture?
Knowledge of Quantum Field Theory, General Relativity and String Theory at the level of a Master course.
SPA Academics: 
Ricardo Monteiro