Decomposition 2021

Contribution List

1. Welcome / orientation

5/22/21, 8:50 AM

2. Yuya Tanizaki: Modified instanton sum in 4d gauge theories

5/22/21, 9:00 AM

Abstract: In the path integral formulation of quantum field theories (QFTs), we are supposed to sum up all possible field configurations to ensure the locality in the usual lore. In the case of 4d gauge theories, this would require us to sum up all the instanton sectors, which topologically classify the gauge-field configurations in the closed spacetime. However, it turns out that this is not...

3. Mauricio Romo: A GLSM view on Homological Projective Duality

5/22/21, 10:00 AM

Abstract: I will present a rather general construction of homological projective dual (HPD) pairs using gauged linear sigma models. In mathematical terms, HPD can be viewed as a tool to generate semiorthogonal decompositions. In physical terms, HPD pairs are phases of GLSMs whose categories of B-branes are related in a very precise way (and if some conditions are met, equivalent). I will...

8. Theodore Jacobson: Lifetimes of near-eternal false vacua

5/22/21, 2:00 PM

Abstract: We consider examples of extremely long lived false vacua which arise in theories with approximate or emergent (d-1)-form symmetries. In the limit that these symmetries are exact, decomposition of the theory into 'universes' implies that certain false vacua are exactly stable. We look at cases where the false vacua in question arise near symmetric points in parameter space where the...

4. Daniel Robbins: Decomposition in orbifolds with discrete torsion

5/22/21, 3:00 PM

Abstract: In the context of 2D CFT, decomposition occurs when we construct an orbifold of a theory by a group G that has a trivially-acting subgroup K. The resulting theory is a disjoint union of orbifolds by subgroups of the effective G/K symmetry. We'll describe how turning on discrete torsion in G affects the story, including opening the possibility that the disjoint union contains only a...

5. Richard Eager: Elliptic genera of pure gauge theories in two dimensions

5/23/21, 9:00 AM

Abstract: I will explain how to compute the elliptic genera of (2,2) supersymmetric gauge theories in two dimensions with gauge group G/Gamma (for G semisimple and simply-connected, Gamma a subgroup of the center of G) with various discrete theta angles. The two new ingredients are a systematic study of the moduli space of flat G/Gamma connections on the torus and an efficient organization...

6. Hsian-Hua Tseng: On the Gromov-Witten theory of etale gerbes

5/23/21, 10:00 AM

Abstract: We aim to give a review of results on how Gromov-Witten invariants of etale gerbes respect the decomposition conjecture, from the speaker's own perspective.

7. Zohar Komargodski

5/23/21, 3:00 PM