HET Journal Club: Anders Wallberg

Speaker: Anders Wallberg (CERN & Lausanne)

Title: Orientifolds, Crosscaps & Integrability: N=4 SYM on RP^4

Abstract: Orientifold planes are enigmatic objects in string theory: they have no independent localised dynamical degrees of freedom and can carry negative tension, while their non-perturbative description remains challenging. I will discuss a setting in which protected observables provide non-perturbative data in the presence of an orientifold: N=4 SYM on RP^4, defined by combining an antipodal identification on spacetime with an R-symmetry reflection and charge conjugation of the SU(N) gauge group. At weak coupling, planar tree-level one-point functions are described by spin-chain crosscap overlaps, providing evidence for preserved integrability. At strong coupling, I will identify the associated classical worldsheet crosscap and probe O1-plane, and discuss the quantum crosscap in the pp-wave limit. Supersymmetric localisation yields finite-coupling half-BPS one-point functions; time permitting, I will explain the matrix model and discuss its weak-coupling and BMN limits.