Seminars & Talks

Title: Quotient Quiver Subtraction – Classical Groups

Seminar: Geometry and Theoretical Physics Seminar, Imperial College London

Date: 16.06.2026

Abstract: I will demonstrate new combinatorial techniques on quivers with unitary gauge groups which gauge Sp(n), SO(n), and Sp(n)+1/2F subgroups of Coulomb branch global symmetries. Geometrically, these correspond to performing a hyper-Kähler quotient on the Coulomb branch. The techniques involve a “quiver subtraction” along with changing the graph-type of the end of the quiver to type D, C, or B. Each technique will be illustrated with simple examples.

The notes for this whiteboard talk are attached.

Title:  Gauging global symmetries with magnetic quivers

Seminar: Theoretical Physics Group Seminar, Università degli Studi di Milano-Bicocca (Milan, Italy)

Date: 23.04.2025

Abstract: The gauging of Coulomb branch isometry subgroups of 3d N=4 quiver gauge theories can be realised through simple combinatorial operations on quivers. The effect on the Coulomb branch is a hyper-Kähler quotient. In this talk I will introduce these combinatorial techniques, called quotient quiver subtraction and quiver polymerisation. These techniques will be illustrated by examples from a variety of physical contexts including the moduli space of instantons, four dimensional theories, and the six dimensional (E6,E6) minimal conformal matter theory.ferred to as minimal (E6,E6) conformal matter. 

Title: Orthosymplectic quotient quiver subtraction

Seminar: Quiver Meeting, Imperial College London and University of Oxford

Date: 07.03.2025

Abstract: The gauging of Coulomb branch isometry subgroups of 3d N=4 quiver gauge theories can be realised through simple combinatorial operations on quivers. The effect on the Coulomb branch is a hyper-Kähler quotient. In this talk I will introduce orthosymplectic quotient quiver subtraction, which gauges SU(2), SU(3), G2, and SO(7) subgroups of the Coulomb branch isometry of unframed orthosymplectic quivers. This algorithm has origins in 6d N=(1,0) through Type IIA brane systems and magnetic quivers. I will demonstrate features of the algorithm through examples, which are mostly drawn from nilpotent orbit closures. Along the way we will encounter new orthosymplectic quivers which have unitary counterparts as well as constructions of certain F4 nilpotent orbits which were not known before. Finally, I will use orthosymplectic quotient quiver subtraction to give a novel magnetic quiver for the Higgs branch of the 6d N=(1,0) worldvolume theory of two ½ M5 branes on E6 Klein singularity and one M5 brane on E6 Klein singularity. The latter is often referred to as minimal (E6,E6) conformal matter. 

Title: Quiver Polymerisation

Conference: Iberian Strings 2025, Bilbao, Spain

Dates: 15.01.25 - 17.01.25

This was a poster presented at the Iberian Strings 2025 conference in Bilbao, Spain. 

The poster is based on one of my publications called "Quiver Polymerisation", Journal of High Energy Physics, vol. 11, p. 168, 2024.

Title: Quotient quiver subtraction

Seminar: Geometry and Theoretical Physics Seminar, Imperial College London

Date: 11.02.2025

Abstract: I will present a technique called “quotient quiver subtraction” which, in physics language, gauges subgroups of Coulomb branch global symmetries. The action on the Coulomb branch is a hyper-Kähler quotient. I will demonstrate the features of this algorithm with many examples, mostly drawn from Coulomb branch constructions of nilpotent orbit closures. Along the way we will encounter new relationships between nilpotent orbit closures and other varieties such as Slodowy slices and affine Grassmannian slices, including those of exceptional type. These examples may be viewed as an extension of the work of Kostant-Brylinski and Kobak-Swann to actions on nilpotent orbit closures by non-Abelian continuous groups.

Title: SU(n) hyper-Kähler quotients of Coulomb branches of 3d N=4 quiver gauge theories

Seminar: Quiver Meeting, Imperial College London and University of Oxford

Date: 03.11.2023

Abstract: The difficult problem of gauging Coulomb branches of 3d N=4 quiver gauge theories has been tackled from a class S perspective in the past. In this talk, I will present some first steps in viewing Coulomb branch gauging/hyper-Kähler quotient as a quiver subtraction. This quiver subtraction can produce the gauging of an SU(n) subgroup of the Coulomb branch global symmetry of a unitary quiver gauge theory beyond class S theories. This involves the subtraction of a "bad" quiver, in the sense of Gaiotto and Witten, and has an interpretation in class S as a Riemann surface with two maximal punctures. I will outline some of the rules of this quiver subtraction and present many examples which highlight the structure of the resulting moduli spaces. Particularly interesting outcomes involve relationships between nilpotent orbit closures, affine Grassmannian slices, and Slodowy slices and intersections. Many of these relationships have not been found in the mathematics literature before. This is based on a joint work ArXiv: 2308.05853 with Amihay Hanany and Rudolph Kalveks. 

Title: Coulomb branches: quiver subtraction, magnetic quivers, the monopole formula [2/2]

Seminar: Geometry and Theoretical Physics Seminar, Imperial College London

Date: 31.10.2023

Second part of a mini lecture series aimed towards mathematicians on physics based techniques for calculation and study of symplectic singularities.

Title: Coulomb branches: quiver subtraction, magnetic quivers, the monopole formula [1/2]

Seminar: Geometry and Theoretical Physics Seminar, Imperial College London

Date: 24.10.2023

First part of a mini lecture series aimed towards mathematicians on physics based techniques for calculation and study of symplectic singularities.