Target Space Geometry for Topological Strings - Charles Strickland-Constable (University of Hertfordshire) Room: Kjølv Egelands Hus, room E-102 Using generalised geometry, I will describe a universal construction of a double complex on supersymmetric NS-NS backgrounds which provides a geometric realisation of the BRST complex of twisted string sigma models. It will also be shown how to write the 1-loop partition function in terms of these objects. For the case of G2 manifolds, I will show how this leads to a target space action which reproduces the 1-loop partition function.

Carrollian gravity from the gauging procedure - José Figueroa-O'Farrill (The University of Edinburgh) Room: Kjølv Egelands Hus, room E-102 I will report on recent work with Emil Have, Stefan Prohazka and Jakob Salzer where we rephrase the gauging procedure in terms of Cartan geometry and apply it to derive carrollian theories of gravity. I will concentrate on two examples of what could be mis-labelled “gauging the Poincaré algebra”: the classic derivation of GR in the first-order formalism and a novel derivation of a version of carrollian gravity.

Twisting with a Flip - Guido Festuccia (Uppsala University) Room: Kjølv Egelands Hus, room E-102 I will consider N=2 supersymmetric gauge theories on 4D compact manifolds with a Killing vector field with isolated fixed points. Studying the realization of supersymmetry in these theories leads to consider a generalization of the notion of self-duality allowing to construct a framework unifying equivariant Donaldson-Witten theory and Pestun's theory on S4 and its generalizations. By dimensional reduction this framework allows us also to reformulate N=2,2 supersymmetric theories on compact two manifolds. -------------------------- Join Zoom Meeting https://stavanger.zoom.us/j/69012564647?pwd=cjBVQXBJcXM1WEFNcWFQZ1Erd3lVQT09 Meeting ID: 690 1256 4647 Password: 854146

Heterotic Systems: Geometry and Moduli - Xenia de la Ossa (University of Oxford) Room: Kjølv Egelands Hus, room E-102 Abstract tba

A non-Lorentzian Approach to non-Lagrangian CFT's - Neil Lambert (King's College London) Room: Kjølv Egelands Hus, room E-102 We discuss interacting five-dimensional gauge theories with an OSp(6|4) symmetry group - same as ABJM - but with the role of spacetime and R-symmetries interchanged. These are obtained by a conformal compactification of six-dimensional SCFT’s and admit towers of Omega-deformed instantons that reproduce the KK spectrum. The SU(1,3) spacetime symmetry places interesting constraints on the correlation functions which can be used to reconstruct the six-dimensional correlators. In the limit that the Omega-deformation is turned off one recovers the standard DLCQ construction and associated Schrodinger Symmetry.

K3 Degeneration, Orientifolds and Duality - Chris Hull (Imperial College London) Room: Kjølv Egelands Hus, room E-102 Abstract tba

Heterotic Strings on T3/Z2, Nikulin involutions and M-theory - Ida Zadeh (ICTP, Trieste) Room: Kjølv Egelands Hus, room E-102 I will discuss compactification of the heterotic string on the smooth, flat 3-manifold T3/Z2, without supersymmetry. The low energy dynamics of the corresponding ten-dimensional heterotic supergravity will be described. The semi-classical theory has both Coulomb and Higgs branches of non-supersymmetric vacua. An exact worldsheet description of the compactification will then be presented using the framework of asymmetric orbifolds of T3 , where the orbifold generator involves a Nikulin non-symplectic involution of the even self-dual lattice of signature (19,3). This construction gives a novel conformal field theory description of the semi-classical field theory moduli space and reveals a rich pattern of transitions amongst Higgs and Coulomb branches. ----------------------------------------------------- Join Zoom Meeting https://stavanger.zoom.us/j/63647494163?pwd=ZzNQWVl4dlhaMGRtbktRZUN1dElaQT09 Meeting ID: 636 4749 4163 Password: 165388

Black Holes, Attractor Points and Arithmetic - Philip Candelas (University of Oxford) Room: Kjølv Egelands Hus, room E-102 I will give an explicit description of a Calabi-Yau threefold which becomes, for certain values of the parameter, an attractor variety of rank 2. The periods of this variety have remarkable number-theoretic properties which will be reviewed. This reports on joint work with X de la Ossa, Mohamed Elmi and Duco van Straten, and earlier work with Xenia de la Ossa and Duco van Straten.

Reflections on Mirror Symmetry - Colloquium by Xenia de la Ossa (University of Oxford) Room: Kjølv Egelands Hus, room E-102 A historical introduction to counting rational curves in Calabi Yau manifolds