Mon, 09 Nov 2015

12:00 - 13:00
L3

Yang-Mills origin of gravitational symmetries

Mike Duff
(Imperial College)
Abstract

By regarding gravity as the convolution of left and right Yang-Mills theories together with a spectator scalar field in the bi-adjoint representation, we derive in linearised approximation the gravitational symmetries of general covariance, p-form gauge invariance, local Lorentz invariance and local supersymmetry from the flat space Yang-Mills symmetries of local gauge invariance and global super-Poincare. As a concrete example we focus on the new-minimal (12+12) off-shell version of simple four-dimensional supergravity obtained by tensoring the off-shell Yang-Mills multiplets (4+4,NL =1)and(3+0,NR =0). 

 
Thu, 29 Oct 2015

16:00 - 17:00
C5
Mon, 26 Oct 2015
15:45
Oxford-Man Institute

Liouville quantum gravity as a mating of trees

Jason Peter Miller
(MIT)
Abstract

There is a simple way to “glue together” a coupled pair of continuum random trees to produce a topological sphere. The sphere comes equipped with a measure and a space-filling curve (which describes the “interface” between the trees). We present an explicit and canonical way to embed the sphere into the Riemann sphere. In this embedding, the measure is Liouville quantum gravity with parameter gamma in (0,2), and the curve is space-filling version of SLE with kappa=16/gamma^2. Based on joint work with Bertrand Duplantier and Scott Sheffield

Tue, 03 Nov 2015

16:00 - 17:00
C5

Equivalence relations for quadratic forms

Detlev Hoffmann
(Dortmund)
Abstract

We investigate equivalence relations for quadratic forms that can be expressed in terms of algebro-geometric properties of their associated quadrics, more precisely, birational, stably birational and motivic equivalence, and isomorphism of quadrics. We provide some examples and counterexamples and highlight some important open problems.

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