Closed Bosonic String Field Theory At Quartic Order

TL;DR

This paper provides a detailed numerical analysis of the four-point contact interaction in closed bosonic string field theory, including the geometry of moduli space and local coordinate descriptions, enabling precise computations of string interactions.

Contribution

It offers a comprehensive numerical characterization of the moduli space boundary and local coordinates for four-punctured spheres in closed bosonic string field theory, with detailed methods and fitted results.

Findings

Computed the boundary of the moduli space for four-punctured spheres

Provided local coordinates around punctures using Strebel quadratic differentials

Generated fits for computing contact interactions of off-shell string states

Abstract

We give a complete numerical description of the geometry of the four-point contact interaction of closed bosonic string field theory. Namely, we compute the boundary of the relevant region of the moduli space of the four-punctured spheres, and everywhere in this region we give the local coordinates around each punctures in terms of a Strebel quadratic differential and mapping radii. The numerical methods are explained in details. And the results are translated into fits, which can in principle be used to compute the contact interaction of any four off-shell string states.