He is known for his discovery, with Stephen Parke, of Parke–Taylor amplitudes, also known as maximally helicity violating (MHV) amplitudes ; his pioneering use of supersymmetry for computing scattering amplitudes in quantum chromodynamics ; his seminal work, with Ignatios Antoniadis, Edi Gava and Kumar Narain, on topological string amplitudes; his formulation, with Ignatios Antoniadis and Hervé Partouche, of the first four-dimensional quantum field theory with partial supersymmetry breaking ; his extensive studies, with Stephan Stieberger, of superstring scattering amplitudes.