11:00 Charles Thull - Seven-dimensional super-Yang-Mills at negative coupling.
A stack of D6 branes in type IIA string theory admits two distinct low energy regimes. We show that these two regimes know about each other. We start from the weakly coupled seven-dimensional super-Yang-Mills theory and use supersymmetric localization to compute its sphere partition function. This admits a regime of negative effective 't Hooft coupling. Here, the non-perturbative contributions to the partition function become important and in the small negative coupling limit we find weakly tensioned instanton membranes. We understand these as part of a weakly coupled seven-dimensional supergravity theory, the second IR regime for the D6 brane stack.
14:00 Sabine Harribey - A quick introduction to melonic CFTs.
Random tensors exhibit a melonic large-$N$ limit, which is both richer than the large-$N$ limit of vector models and simpler than the planar limit of matrix models. They were first introduced in zero dimension in the context of random geometry and quantum gravity. They were then generalised in $d$ dimensions where they can be studied as proper quantum field theories. In this context, they give rise in the infrared to a new type of CFTs, analytically accessible, called melonic CFTs.
After briefly reviewing the history of tensor models, I will present in particular the long-range $O(N)^3$ bosonic tensor model. In the large-N limit, but non-perturbatively in the coupling constants, we showed the existence of a stable, strongly-interacting line of fixed points. We also found strong hints of unitarity at large N. These results can then be used to study properties of QFTs in rigorous set-ups. For example, we recently showed that this model gives a new non-trivial example of the $F$-theorem.
