PGI Seminar Series Fall 2022|Sam Collingbourne|Columbia University|"The Gregory--Laflamme Instability of the 5D Schwarzschild Black String Exterior"

Nov 7, 2022, 12:30 pm1:30 pm
Event Description

I will discuss a direct rigorous mathematical proof of the Gregory--Laflamme instability for the 5D Schwarzschild black string. This is a mode instability at the level of the linearised vacuum Einstein equation. Under a choice of ansatz for the perturbation and a gauge choice, the linearised vacuum Einstein equation can be reduced to a Schrödinger eigenvalue equation to which an energy functional is assigned. It is then shown by direct variational methods that the lowest eigenfunction gives rise to an exponentially growing mode solution which has admissible behaviour at the future event horizon and spacelike infinity in harmonic/transverse-traceless gauge.