Lead organiser : Neil Lambert
The talks of the Theoretical Physics workshop will be held in room S-2.08 of the Strand Building.
Tea & Coffee will be offered in the Bush House Arcade.
The talks of the Theoretical Physics workshop will be held in room S-2.08 of the Strand Building.
Tea & Coffee will be offered in the Bush House Arcade.
Invited speakers
Tim Adamo
U. of Edinburgh UK |
Cyril Closset
Birmingham U. UK |
Madalena Lemos
Durham University UK |
Jan Manschot
Trinity College Ireland |
Mario Martone
King's College London UK |
Bogdan Stefanski
City U. of London UK |
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Tuesday 7th 14.15 - 15.10: Mario Martone
15.10 - 16.05: Madalena Lemos 16.05 - 16.45: Tea & Coffee [BH(N) Arcade] 16.45 - 17.40: Bogdan Stefanski |
Wednesday 8th 14.15 - 15.10: Jan Manschot
15.10 - 16.05: Cyril Closset 16.05 - 16.45: Tea & Coffee [BH(N) Arcade] 16.45 - 17.40: Tim Adamo |
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Mario Martone
Chiral algebras’ finite extension in Argyres-Douglas theories Abstract. The operator spectrum of four dimensional superconformal field theories (SCFTs) has the striking property that there exists a subsector carrying the structure of a chiral or vertex operator algebra – a close cousin of a two dimensional CFT. Identifying the corresponding chiral algebra, given some SCFT data, has then become a popular enterprise. I will describe some subtleties which can arise and outline how the geometry of the moduli space can be used to resolve them. In particular we will derive that the chiral algebra associated to an infinite series of Argyres-Douglas theories is a finite extension of what has been initially thought. |
Jan Manschot
Domains for running couplings and four-manifold invariants Abstract. A manifestation of S-duality or strong-weak coupling duality is the equivalent dynamics of a quantum field theory at distinct values of its coupling constant. A natural question for such a quantum field theory is the determination of a domain for the coupling constant parametrizing inequivalent quantum field theories. I will discuss this question for 4d and 5d N = 2 supersymmetric Yang-Mills theories with gauge group SU(2). For generic choices of parameters, it is shown that the domain includes branch points and cuts. In the last part of the talk, I will apply these methods to the evaluation of topological correlators of YM theories supported on a smooth, compact four-manifold. These correlators correspond to four-manifold invariants in mathematics, such as Donaldson invariants and generalizations. |
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Madalena Lemos
Regge trajectories for N=(2,0) superconformal field theories Abstract. The spectrum of conformal field theories displays Regge trajectories: families of operators whose dimensions are smooth functions of the spin. We discuss the structure of Regge trajectories of the six-dimensional N=(2,0) SCFTs, in particular of operators coupling to the stress tensors super-multiplet. We show how these operators organize themselves in Regge trajectories starting at spin -3, and how different Regge trajectories are intertwined by supersymmetry. We then describe an iterative procedure to "bootstrap" the stress tensor multiplet four-point function using the Lorentzian inversion formula. Taking as input protected data we obtain an approximate low twist spectrum and compare it rigorous numerical bootstrap bounds. |
Cyril Closset
5d SCFTs, Seiberg-Witten geometry and partition functions Abstract. Five-dimensional superconformal field theories remain rather mysterious beasts. We mostly understand them through string-theory arguments, but also through their mass deformations to five-dimensional gauge theories. By dimensionally reducing these 5d SCFTs on a circle, we obtain 4d N=2 supersymmetric QFTs "of Kaluza-Klein (KK) type", and this perspective is very useful to understand the 5d physics. I will discuss aspects of the Seiberg-Witten geometry governing the Coulomb branch of rank-one 4d N=2 supersymmetric KK theories, and how the 4d perspective simplifies the computation of partitions functions on five-manifolds. |
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Bogdan Stefanski
Exact results for low-supersymmetry D-instantons Abstract. I will review recent computations of D-instanton effects in backgrounds with N=2 and N=1 supersymmetry. Using first-principle String Field Theory methods, we derive leading D-instanton correction exactly, including all numerical factors and without any additional assumptions. Applied to N=2 theories, we compute non-perturbative corrections to the hypermultiplet moduli space metric finding agreement with predictions in the literature. In generic N=1 backgrounds with no flux, we compute the D-instanton contribution to the superpotential, including the exact normalisation, and prove its holomorphicity. |
Tim Adamo
Gravitational scattering and Hyperkähler geometry Abstract. From the perspective of traditional perturbation theory, the computation of gravitational scattering amplitudes is a nightmare, as the non-linearities of general relativity induce an infinite number of Feynman rules. Yet in recent years, remarkably compact formulae for tree-level graviton scattering have been discovered whose origins in classical general relativity are obscure. I will discuss how these expressions can be derived from first principles using the interplay between perturbative general relativity, hyperkähler geometry and twistor theory. This perspective also enables new calculations for gravitational scattering in curved space-time that are not accessible with other approaches. |