Research lectures, seminars and events
The events listed in this area are research seminars, workshops and lectures hosted by Durham University departments and research institutes. If you are not a member of the University, but wish to enquire about attending one of the events please contact the organiser or host department.
|September 2017||November 2017|
Events for 6 October 2017
Philippe Spindel: Minisuperspace Quantum Supersymmetric Cosmology (and its Hidden Kac-Moody Structures)
I describe the quantisation of the dimensional reduction to one timelike dimension of N=1, D=4 supergravity on a SU(2) group manifold, taking into account all nonlinear fermionic terms of the dynamic. The quantisation leads to a 64 dimensional Hilbert space that provides a representation of operators from which the supersymmetric and Hamiltonian constraints are built. These operators generate a representation of the maximally compact sub-algebra $K(AE_3)$ of the rank-3 Kac-Moody algebra $AE_3$. The quartic-in-fermions term of the Hamiltonian constraint presents remarkable algebraic and physical properties, one of them being a possible quantum avoidance of the cosmological singularity. Moreover a 50 dimensional subspace of the Hilbert space admit propagating solutions of the constraint equations that carry a chaotic spinorial dynamic described asymptotically by reflection operators generalising the classical Coxeter relations and defining a spinorial extension of the Weyl group of $AE_3$.
(based on arXiv : 1406.1309, Phys. Rev. D 90 (2014) 10, 103509; arXiv : 1704.08116, Phys. Rev. D 95 (2017) 12, 126011)
Antonin Chambolle: Phase-field approximations of Griffith energies and the non-interpenetration of fractures
We discuss numerical approaches for the computation of cracks in a brittle material, and of their evolution. We address the issue of interpenetration of the crack, and the numerical analysis of methods which have been proposed to prevent it.
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