Current trimester: Flavors of Amplitudes
Next trimester (spring): TQFT and Knot Theory, kickoff at IHP: 22.04.2026. More info soon, stay tuned!
Scattering amplitude of closed strings at genus one
byMehregan Doroudiani
Abstract:Perturbative calculations of string amplitudes are twofold: an expansion in the string coupling (the genus expansion of the worldsheet) and a low-energy expansion in the momenta. In this talk, I will focus on the low-energy expansion of closed string amplitudes at genus one, specifically for four- and five-point massless states of type IIB superstrings in flat spacetime. Evaluating these amplitudes involves integrating over the moduli space of punctured tori. I will demonstrate how the formalism of equivariant iterated Eisenstein integrals can be used to systematically calculate these integrals. Additionally, I will discuss the implications of these results for the S-duality of type IIB and conclude by exploring the underlying number-theoretic aspects of string amplitudes.