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Résumé |
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 RP4, 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. |
