Geometric Flows and Nearly-Parallel G2-Structures

Fri Oct 13, 2023 2:00 p.m.—3:00 p.m.
Exterior of Sheffield-Sterling-Strathcona Hall featuring a stone carving of Yale's coat of arms and motto

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Seminar: 
Geometric Analysis and Application

Event time: 
Friday, October 13, 2023 - 2:00pm

Location: 
KT 906

Speaker: 
Aaron Kennon

Speaker affiliation: 
UC Santa Barbara

Event description: 
A 3-Sasakian structure on a 7-manifold may be used to define two distinct Einstein metrics: the 3-Sasakian metric and the squashed Einstein metric. Both metrics are induced by nearly parallel G2-structures which may also be expressed in terms of the 3-Sasakian structure. Just as Einstein metrics are critical points for the Ricci flow up to rescaling, nearly parallel G2-structures provide natural critical points of the (rescaled) geometric flows of G2-structures known as the Laplacian flow and Laplacian coflow. We study each of these flows in the 3-Sasakian setting and see that their behaviour is markedly different, particularly regarding the stability of the nearly parallel G2-structures. We also compare the behaviour of the flows of G2-structures with the (rescaled) Ricci flow. This was joint work with Jason Lotay