From Fields to Strings

<!--HTML--><p>I will describe a mechanism to reorganize the Feynman diagrams of a perturbative large N gauge theory into localized integrals over closed string moduli space using the Strebel parametrization of the latter. This will be explicitly illustrated for free symmetric product orbifold CFTs where holomorphic covering maps play a key role. After recasting these covering maps in terms of dual worldsheet twistor fields in $AdS_3$, it will be generalized for $AdS_5$. &nbsp;Imposing appropriate reality conditions, I will discuss a proposed stringy incidence relation. For correlators of free $\mathcal{N}=4$ SYM with special kinematics, I will then show an explicit construction of these twistor covering maps, where the regularized "Strebel area" of the worldsheet corresponding to these maps, reproduces the Feynman propagator.&nbsp;</p>