Open-closed duality suggests that a single closed string theory may admit more than one open string realization.This concept is developed by Gopakumar and the collaborators. In this talk, I will discuss such an open-closed-open structure in a protected sector of four-dimensional N=4 super Yang–Mills theory, focusing on half-BPS three-point functions with determinant operators associated with giant gravitons. The gauge theory correlator admits a Gaussian three-matrix description, which we regard as a V-type open string model. By reorganizing the color and flavor degrees of freedom, one obtains a second, F-type description in terms of bifundamental matrices on a triangular quiver. Compared with the two-point case, the three-point problem is qualitatively richer: the quiver allows oriented cubic closed walks and the associated ribbon graphs are no longer necessarily bipartite. I will explain several checks of the relation between the two descriptions, including exact finite N results in the single giant sector, the large N saddle-point analysis, and a character expansion that makes the finite N combinatorial correspondence explicit. Finally, I will discuss the closed string interpretation of the same Feynman graphs. Connected contractions define three-colored integer Strebel surfaces, while the loss of bipartiteness leads to a modified target space construction based on a barycentrically subdivided Belyi map. This talk is based on the paper arXiv:2609.04621.
Zoom Meeting: https://zoom.us/j/98991509615?pwd=CaxLuNfBiCGhbIHbBh9kJ50bHubKDw.1
Meeting ID: 989 9150 9615
Passcode: 262621