STAMP is a crossdisciplinary student seminar which launched in
August 2022 to bring together PG students working in theoretical
and mathematical physics in Edinburgh. It seeks to repair links
between the different research groups which were broken during
the Covid pandemic, forge new ones, and give PG students a
friendly environment to share their research and hear about what
their peers are working on.
STAMP is primary aimed at PhD students in EMPG (University of
Edinburgh and HeriotWatt) and the Higgs Centre, but we welcome
any students and junior researchers who wish to join us.
The STAMP organisers are grateful for the funding they have
recieved from the Higgs Centre and from the School of
Mathematics at University of Edinburgh.
STAMP is currently organised by
Andrew Beckett,
Linden DisneyHogg and
Conor Elrick.

16th February 2023
Bayes Centre 5.45 (Central Campus)
Skyrmions in the gauged Sigma model of chiral magnets
Peter Gerlagh (HWU, EMPG)
We characterise skyrmions in Bogomolny models of chiral magnets without axisymetry.
We show a duality between these Bogomolny models and the specific Bogomolny model wherein the socalled DMI tensor is rank one.
The potential in these models have two separate minimums and corresponding stationary vacuums.
Exact solutions with skyrmions are built around a domain wall which separates these vacuums.
The domain walls themselves can be characterised by a position and an angle.

23rd February 2023
No Event (Reading week + SoPA student retreat)

2nd March 2023
Bayes Centre 5.45 (Central Campus)
Pedagogical Introduction to Higher Principal Bundles
Dominik Rist (HWU, EMPG)
From the Standard Model of particle physics to condensed matter systems,
gauge theories form a powerful framework to understand Nature. Mathematically, gauge fields
correspond to connections on principal bundles, which are described by Lie algebra valued
1forms. String theory considerations motivate the lift of this picture to a categorified
setting. Principal bundles are lifted to higher principal bundles (or gerbes) and higher
connections are then described by higher degree forms valued in some Linfinity algebra. In
this lecture, I will introduce these notions underpinning the geometric framework of higher
gauge theory, reviewing elements of higher category theory along the way. In particular, the
emphasis in this lecture will be on the cocycle description of gerbes with connection.
Click here for Dominik's notes.

9th March 2023
Higgs Centre (JCMB, Kings Buildings)
The Bethe ansatz in practice: an application to a minimal model in nonequilibrium statistical physics
Ivan Lobaskin (UoE, SoPA, Institute for Condensed Matter and Complex Systems)
Integrable systems are, loosely speaking, models that can be solved exactly
using certain standard methods. For quantum and stochastic 1D lattice models, this method is the
Bethe ansatz. Despite this, in physics, integrability techniques have a reputation of being
excessively formal and opaque. Indeed, even when a formal exact solution is given, it can be a
nontrivial task to translate this into meaningful statements regarding physical observables. In
an effort to challenge this stigma, in this seminar, I will present a classic calculation, in
which the Bethe ansatz is used to directly calculate physical observables for a toy model of
nonequilibrium statiscial mechanics. Specifically, I will calculate the long time current
statistics in a totally asymmetric simple exclusion process  the ``Ising model of
nonequilibrium statistical physics".
Ref: arXiv:condmat/9809044

16th March 2023
Bayes Centre 5.45 (Central Campus)
Chasing Motes: A Physicist's introduction to Hopf Algebras
Sam Teale (UoE, SoPA, PPT)
Hopf Algebras are examples of bialgebras, being both an algebra and coalgebra and
are additionally equipped with an endomorphism known as an antipode which is analogous to the map of
groups that takes elements to their inverse. These structures have been studied since 1941 first in
the field of algebraic topology and have since spread to many fields of mathematics. More recently they
have been applied to quantum mechanics and the combinatorics of renormalization of quantum field theories.
In this talk I will introduce Hopf algebras for a very general audience; work through a couple of simple
examples; and finally, discuss the Motic Hopf algebra and its relevance to my work in renormalization.

23rd March 2023
Higgs Centre (JCMB, Kings Buildings)
A look at some ``Axioms for the category of Hilbert spaces (and linear contractions)''
Nesta van der Schaaf (University of Edinburgh, School of Informatics, LFCS)
We'll have a look at a new result that characterises Hilbert
spaces (and linear contractions) in terms of categorical axioms that do
not refer to probabilities, complex numbers, inner products,
continuity, convexity, or dimension. To avoid going into too many
technical details, I will try to motivate the axioms and broader
research landscape (categorical quantum mechanics) by drawing analogies
to familiar terminology of sets and Hilbert spaces. (Based on joint
work with Chris Heunen and Andre Kornell.)
Ref: arXiv:2211.02688

30th March 2023
Bayes Centre 5.45 (Central Campus)
An Introduction to QCD Sum Rules
Matthew Rowe (UoE, SoPA)
Abstract: QCD sum rules provide an elegant way of accessing non
perturbative physics using the tools of perturbation theory. In this
talk I will attempt a relatively selfcontained introduction to QCD
sum rules using the classic example of pseudoscalar correlators to
calculate meson decay constants. I will then discuss some practical
matters and complications and, if time permits, some new applications
from my own work.

6th April 2023
JCMB 1501 (Kings Buildings)
Algebraic structures in higherspin gravity
Simon Pekar (University of Mons; visiting UoE, EMPG)
Higherspin gravity refers to an extension of general relativity
involving fields with spin higher than two. The problem of finding a
consistent interacting theory of higherspin gravity can be
reformulated into algebraic terms, whose solution is surprisingly
simple and rigid.
We first describe the construction of a higherspin symmetry algebra in
the case of exact higherspin symmetry, and make some comments
regarding its holographic interpretation. We then turn to the problem
of ``slightly broken'' higherspin symmetry, which involves a certain
deformation of the infinitedimensional symmetry into a $A_\infty$
algebra.

13th April 2023
Bayes Centre 5.45 (Central Campus)
3d gravity as a source of integrable systems and hierarchies
Juan Carlos Morales Parra (HWU, EMPG)
In 1988 Witten showed the theory of (pure) General Relativity
in 3 dimensions is exactly solvable, using an “equivalent” ChernSimons
formulation. In this talk we will describe the theory using the Newman
Penrose formalism and explicitly show how the equations of motion
reduce to an AKNS system, proving in this way its integrability in a
more direct way. Then we will see how boundary conditions for higher
spin 3d gravity naturally provide hierarchies of integrable systems.
Explicitly, we will see how to obtain the mBoussinesq hierarchy from
boundary conditions in spin3 gravity on AdS_3 and how the boundary
dynamics of the theory could be completely described in terms of this
family of integrable systems.
Click here for Juan Carlos's slides.

20th April 2023
Higgs Centre (JCMB, Kings Buildings)
SemiInfinite Cohomology and Potential Applications to NonLorentzian Physics
Girish Vishwa (UoE, EMPG)

27th April 2023
Bayes Centre 5.45 (Central Campus)
Higher categories, representation theory, and noninvertible symmetries from 6D N=(2,0) SCFTs
Veronica Pasquarella (University of Cambridge, DAMTP)
With this talk, I wish to highlight the intertwining nature of higher
category theory and gauge theory, with representation theory being the
binding element in between them. 6D N=(2,0) SCFTs being the natural
realm where this correspondence takes place, I will show that the
categorical understanding of class S theories and the emergence of non
invertible symmetries, can be traced back to the behaviour of the
condensation of homomorphisms in the Symmetry Topological Field Theory
(SymTFT), under suitable adaptation of the gaugingbycondensation
procedure.
Veronica's recent preprint on the same topic as her talk: arXiv:2305.18515

4th May 2023
No event (Organisers and planned speaker on GRIFT retreat)

11th May 2023
Bayes Centre 5.45 (Central Campus)
From LandauGinzburg to Matrix factorisations and TQFT
Benjamin Haake (UoE, EMPG)
LandauGinzburg models have been used in various areas of
mathematical physics. For example, there is a close link between them
and sigma models with CalabiYau targets, thus making them interesting
for String theory. Without going into details on these motivations, I
will present LandauGinzburg models as an interesting example of
dealing with boundary terms by introducing additional fields on the
boundary (while partially preserving supersymmetry). The resulting
mathematical structure is matrix factorisation. These can be used to
build TQFTs from LandauGinzburg models which gives a different
perspective on physically known results.

18th May 2023
No Event (Postponed)

25th May 2023
Bayes Centre 5.45 (Central Campus)
Lessons from the Black Hole Information Problem
Benjamin Strittmatter (UoE, EMPG)
Hawking's information puzzle offers a unique perspective on how the
effects of quantum gravity are imprinted on the low energy limit of the
theory. Crucially, unitarity of black hole evaporation demands that the
entropy of Hawking radiation follows a Page curve. In this talk, I aim
to give a pedagogical introduction to the information problem and
explain how holography motivates a gravitational prescription of
computing the finegrained entropy of radiation. Equipped with a better
definition of entropy, we shall see how the tensions around the
information paradox are resolved. Time permitting, I will emphasise the
key role islands and replica wormholes play in this process.