Triangle Seminars
Wednesday, 29 Nov 2017
The classical double copy
📍 London
Christopher White
(QMUL)
Abstract:
Non-abelian gauge theories underlie particle physics, including collision processes at particle accelerators. Recently, quantum scattering probabilities in gauge theories have been shown to be closely related to their counterparts in gravity theories, by the so-called double copy. This suggests a deep relationship between two very different areas of physics, and may lead to new insights into quantum gravity, as well as novel computational methods. This talk will review the double copy for amplitudes, before discussing how it may be extended to describe exact classical solutions such as black holes. Finally, I will discuss hints that the double copy may extend beyond perturbation theory.
Non-abelian gauge theories underlie particle physics, including collision processes at particle accelerators. Recently, quantum scattering probabilities in gauge theories have been shown to be closely related to their counterparts in gravity theories, by the so-called double copy. This suggests a deep relationship between two very different areas of physics, and may lead to new insights into quantum gravity, as well as novel computational methods. This talk will review the double copy for amplitudes, before discussing how it may be extended to describe exact classical solutions such as black holes. Finally, I will discuss hints that the double copy may extend beyond perturbation theory.
Posted by: KCL
RG flows in 3d N=4 gauge theories
Benjamin Assel
(CERN)
Abstract:
I will present a new approach to study the RG flow in 3d N=4 gauge theories, based on an analysis of the Coulomb branch of vacua. The Coulomb branch is described as a complex algebraic variety and important information about the strongly coupled fixed points of the theory can be extracted from the study of its singularities. I will use this framework to study the fixed points of USp(2N) gauge theories with fundamental matter, revealing some surprising features at low amount of matter.
I will present a new approach to study the RG flow in 3d N=4 gauge theories, based on an analysis of the Coulomb branch of vacua. The Coulomb branch is described as a complex algebraic variety and important information about the strongly coupled fixed points of the theory can be extracted from the study of its singularities. I will use this framework to study the fixed points of USp(2N) gauge theories with fundamental matter, revealing some surprising features at low amount of matter.
Posted by: IC
Thursday, 30 Nov 2017
Holographic NJL Interactions
Nick Evans
(U. Southampton)
Abstract:
The NJL model is a classic model of chiral symmetry breaking in QCD and the gauged NJL model underlies many BSM models. I investigate how to apply Witten's double trace prescription in holographic models of quarks to describe NJL interactions. A holographic realisation of NJL and gauged NJL is realised and can be applied to understanding QCD and extended technicolor models.
The NJL model is a classic model of chiral symmetry breaking in QCD and the gauged NJL model underlies many BSM models. I investigate how to apply Witten's double trace prescription in holographic models of quarks to describe NJL interactions. A holographic realisation of NJL and gauged NJL is realised and can be applied to understanding QCD and extended technicolor models.
Posted by: QMW
Friday, 1 Dec 2017
Graduate Mini-course: Holographic combinatorics : 2d Yang Mills theory to tensor models via AdS/CFT
Sanjaye Ramgoolam
(QMUL)
Abstract:
These lectures will be focused on aspects of combinatorics relevant to gauge-string duality (holography).
The physical theories we will discuss include two dimensional Yang Mills
theory, four-dimensional N=4 super Yang Mills
theory with U(N) gauge group, Matrix and tensor models.
The key mathematical concepts include : Schur Weyl-duality,
permutation equivalence classes and associated discrete Fourier
transforms as an approach to counting problems and, branched covers and
Hurwitz spaces. Schur-Weyl duality is a powerful relation between
representations of U(N) and representations of symmetric groups.
Representation theory of symmetric groups offers a method to
define nice bases for functions on equivalence classes of permutations.
These bases are useful in counting gauge invariant functions of
matrices or tensors, as well as computing their correlators in physical
theories. In AdS/CFT these bases have proved useful in identifying
local operators in gauge-theory dual to giant gravitons in AdS.
In the simplest cases of gauge-string duality, the known mathematics
of branched covers and Hurwitz spaces provide the mechanism for the
holographic correspondence between gauge invariants and stringy geometry.
(Lecture 2: Local gauge invariant operators and Hilbert space of CFTs. Young diagrams and Brane geometries. Half-BPS and quarter-BPS. Counting, construction and correlators in group theoretic combinatorics.)
These lectures will be focused on aspects of combinatorics relevant to gauge-string duality (holography).
The physical theories we will discuss include two dimensional Yang Mills
theory, four-dimensional N=4 super Yang Mills
theory with U(N) gauge group, Matrix and tensor models.
The key mathematical concepts include : Schur Weyl-duality,
permutation equivalence classes and associated discrete Fourier
transforms as an approach to counting problems and, branched covers and
Hurwitz spaces. Schur-Weyl duality is a powerful relation between
representations of U(N) and representations of symmetric groups.
Representation theory of symmetric groups offers a method to
define nice bases for functions on equivalence classes of permutations.
These bases are useful in counting gauge invariant functions of
matrices or tensors, as well as computing their correlators in physical
theories. In AdS/CFT these bases have proved useful in identifying
local operators in gauge-theory dual to giant gravitons in AdS.
In the simplest cases of gauge-string duality, the known mathematics
of branched covers and Hurwitz spaces provide the mechanism for the
holographic correspondence between gauge invariants and stringy geometry.
(Lecture 2: Local gauge invariant operators and Hilbert space of CFTs. Young diagrams and Brane geometries. Half-BPS and quarter-BPS. Counting, construction and correlators in group theoretic combinatorics.)
Posted by: QMW