The Octagon Form Factor in \(\mathcal {N}=4\) SYM and Free Fermions
Résumé
The computation of a certain class of polarised four-point functions of heavily charged BPS in \(\mathcal {N}=4\) SYM operators boils down to the computation of a special form factor - the octagon. Here I review the representation of the octagon in terms of free fermions and the determinant formulas that follow. The presentation is based mainly on a common work with Valentina Petkova and Didina Serban[1, 2], but I also mention some recent developments obtained by other authors.