Week 06.05.2024 – 12.05.2024

Wednesday (08 May)

SU(N) Principal Chiral Model at large N

Regular Seminar Evgeny Sobko (LIMS, London)

at:
14:00 KCL
room S0.12
abstract:

I will show how to calculate 1/N expansion of the vacuum energy of the 2D SU(N) Principal Chiral Model for a certain profile of chemical potentials. Combining this expansion with strong coupling I will identify double-scaling limit which bears striking similarities to the c = 1 non-critical string theory and suggests that the double-scaled PCM is dual to a non-critical string with a (2 + 1)-dimensional target space where an additional dimension emerges dynamically from the SU(N) Dynkin diagram. Developing this idea further, I will show how to solve large-N PCM for an arbitrary set of chemical potentials and any interaction strength, a unique result of such kind for an asymptotically free QFT. The solution matches one-loop perturbative calculation at weak coupling, and in the opposite strong-coupling regime exhibits an emergent spacial dimension from the continuum limit of the SU(N) Dynkin diagram. In the second part of my talk I will show that the calculation of the expectation value of half-BPS circular Wilson loops in N = 2 superconformal A_{n−1} quiver gauge theories trivialises in the large n limit (similarly to PCM), construct 1/n expansion, identify DS limit and solve it for any finite value of DS parameter and any profile of coupling constants.

Exponential networks for linear partitions

Regular Seminar Johannes Walcher (Heidelberg)

at:
11:00 IC
room BLKT 112
abstract:

Previous work has given proof and evidence that BPS states in local Calabi-Yau 3-folds can be described and counted by exponential networks on the punctured plane, with the help of a suitable non-abelianization map to the mirror curve. This provides an appealing elementary depiction of moduli of special Lagrangian submanifolds, but so far only a handful of examples have been successfully worked out in detail. In this talk, I will present an explicit correspondence between torus fixed points of the Hilbert scheme of points on ℂ^2⊂ℂ^3 and anomaly free exponential networks attached to the quadratically framed pair of pants. This description realizes an interesting, and seemingly novel, “age decomposition” of linear partitions. We also provide further details about the networks’ perspective on the full D-brane moduli space.