Field theory amplitudes in a space with SU(2) fuzziness

Far Field Amplitudes and Inverse Diffraction Theory

Closed Strings in Misner Space: Stringy Fuzziness with a Twist

Misner space, also known as the Lorentzian orbifold R1,1/boost, is the simplest tree-level solution of string theory with a cosmological singularity. We compute tree-level scattering amplitudes involving twisted states, using operator and current algebra techniques. We find that, due to zero-point quantum fluctuations of the excited modes, twisted strings with a large winding number w are fuzzy...

String Amplitudes from Moyal String Field Theory

We illustrate a basic framework for analytic computations of Feynman graphs using the Moyal star formulation of string field theory. We present efficient methods of computation based on (a) the monoid algebra in noncommutative space and (b) the conventional Feynman rules in Fourier space. The methods apply equally well to perturbative string states or nonperturbative string states involving D-b...

Field-Theory Amplitudes as Resurgent Functions

A series of informal seminars at graduate-student level on the subject of coupling dependence in quantum field theory, with an elementary introduction to the notion of resurgent function that forms the appropriate framework for the coupling dependence of strictly renormalizable theories. While most of the discussion is pedagogical, there are also a few things for the expert: we demonstrate, by ...

Twistor Space Structure Of One-Loop Amplitudes In Gauge Theory

We analyze the twistor space structure of certain one-loop amplitudes in gauge theory. For some amplitudes, we find decompositions that make the twistor structure manifest; for others, we explore the twistor space structure by finding differential equations that the