7th South East Mathematical Physics Seminars

Monday July 11th, 2016

Mathematical Institute, Oxford; lecture room L3 (L5 in the afternoon)


The 7th meeting of the South East Mathematical Physics Seminars (SEMPS) will be held on Monday 11th July 2016 at the Mathematical Insitute, University of Oxford. All talks will be in the lecture room L3/L5 (morning/afternoon) in the mezzanine, with coffee and tea served in the Maths Common Room.

There is no registration fee, but please register here.



Time Speaker Title
10:00 - 10:30   Coffee and tea
10:30 - 11:30 Philip Candelas (Oxford)
Heterotic Geometry
11:45 - 12:30 Martyna Kostacinska (Queen Mary) Two-loop form factors: from N=4 super Yang-Mills to QCD
12:30 - 13:30   Lunch
13:30 - 14:15 Kai Roehrig (Cambridge) Perturbative N=4 SYM in twistor space
14:30 - 15:15 Jennifer Ashcroft (Kent) Scattering Sheep: Kink Collisions in the Presence of False Vacua
15:15 - 15:45   Coffee break
15:45 - 16:30 Jin-Mann Wong (King's College) M5-branes on $M_4$ $\times$ $S^2$
16:45 - 17:30 Antonio Pittelli (Surrey) T-Self Duality and Integrability of AdS$_2$ Superstrings


List of Speakers

Philip Candelas - "Heterotic Geometry"

The simplest compactifications of heterotic string theory on a Calabi-Yau manifold make use of the "standard embedding" in which the background gauge field is identified with the spin connection. These lead to N=2 supersymmetry in spacetime and the moduli spaces of these compactifications are described by special geometry. There has been recent progress on the more general case, where the background gauge field is different from the spin connection. These compactifications correspond to N=1 supersymmetry in spacetime and the moduli spaces are characterised by what we term heterotic geometry. A key role, in deriving this geometry, is played by the anomaly cancellation condition. This talk will be based on joint work with X. de la Ossa and J. McOrist, part of which is reported in arXiv:1605.05256 .

Martyna Kostacinska - "Two-loop form factors: from N=4 super Yang-Mills to QCD"


The study of form factors in maximally supersymmetric Yang-Mills theory has recently been shown to bear relevance for calculations of QCD Higgs + gluon amplitudes in the effective Lagrangian description. With this phenomenological application in mind, we investigate two-loop form factors and remainder functions of non-protected operators belonging to the SU(2|3) closed subsector of N=4 SYM. In the process, we uncover certain hints of universality: firstly, regarding the coincidence of the maximally transcendental part of the result to that of a half-BPS operator and secondly (more surprisingly), across different sectors of the theory. Finally, we use our results to resolve the mixing problem and reconstruct the two-loop dilatation operator in the SU(2|3) sector. The talk is based on the recent work, reported in https://arxiv.org/abs/1606.08682.

Kai Roehrig - "Perturbative N=4 SYM in twistor space"

I will review the developments driving the reformulation of N=4 SYM scattering amplitudes in twistor space. An amazing result of this is a closed form expression for all tree level scattering amplitudes, the RSV-Witten formula. After introducing the relevant mathematical background to understanding this formula, we will take a peak at its
extension loop level.

Jennifer Ashcroft - "Scattering Sheep: Kink Collisions in the Presence of False Vacua"


We investigate numerically head-on kink collisions in a 1+1 dimensional scalar field theory with multiple vacua. The lowest minimum of the potential is called the true vacuum, and any local minima with higher energy are called false vacua. We consider kinks interpolating between false and true vacua, and form four distinct initial configurations from combinations of these kinks. A rich variety of scattering outcomes is found in which, depending on the initial kink set-up and impact velocities, kinks can repel each other, annihilate, form true or false domain walls and reflect off each other.

Jin-Mann Wong - "M5-branes on $M_4$ $\times$ $S^2$"

The study of multiple M5-branes on manifolds $M_{6-n}$ $\times$ $S^n$ for $n = 4,3$ has led to two well-known correspondences: AGT and the 3d-3d correspondence. These relate supersymmetric gauge theories on the n-sphere to conformal/ topological theories on $M_{6-n}$. We determine the theory which arises from compactifying the 6d (2,0) theory on a two-sphere, which is a 4d topological sigma-model into the moduli space of Nahm's equations. We conjecture that this theory is related to a half-twisted 2d (0,2) gauge theory on the two-sphere by a 4d-2d correspondence. 

Antonio Pittelli - "T-Self Duality and Integrability of AdS$_2$ Superstrings"

Dual superconformal symmetry underlies $N=4$ SYM amplitude/Wilson loop duality and, via AdS/CFT, corresponds to the invariance of the AdS$_5$ $\times$ S$^5$ superstring under specific T-dualities. We show that T-self duality holds also for AdS$_2$ $\times$ S$^2$ $\times$ S$^2$ $\times$ T$^4$ superstrings, implying dual superconformal symmetry of the dual CFT$_1$ and giving insights about ABJM’s. We then focus on AdS$_2$ $\times$ S$^2$ $\times$ T$^6$ superstrings and discuss their peculiar integrable worldsheet S-matrix, as well as the infinite dimensional symmetry of the model: the Y[gl$_c$(1|1)] yangian.


Practical Information


Limited funds are available to help with travel expenses of participants with no other source of funding. We hope this will encourage postgraduate students and postdocs to attend the meeting. Please email one of the organisers (at maths.ox.ac.uk) in advance if you would like to apply for funding.

Travel Information and venue

Local travel information can be found here.


Organising Committee: Andrea Ferrari, Yvonne Geyer, Mark Van Loon, Prof. Lionel Mason