BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Scattering of three impulsive gravitational waves and other low re
 gularity problems - Maxime Van De Moortel (DPMMS and Stanford)
DTSTART:20181109T130000Z
DTEND:20181109T140000Z
UID:TALK112039@talks.cam.ac.uk
CONTACT:20674
DESCRIPTION:An impulsive gravitational wave is a weak solution of the Eins
 tein equation\, which models gravitational waves emanating from a strongly
  gravitating source. In the presence of multiple sources\, the impulsive w
 aves eventually interact transversally and it is interesting to study thei
 r scattering.\n\nThe interaction of two general impulsive waves has been u
 nderstood locally in the seminal work of Luk and Rodnianski. They prove th
 at non-linear singularities do not occur in the scattering\, in the sense 
 that space-time stays smooth away from the two waves immediately after the
  interaction.\n\nImpulsive gravitational waves belong to the class of low 
 regularity space-times\, which appear in many interesting topics of classi
 cal General Relativity such as the formation of trapped surfaces\, the str
 ucture of Black Hole interiors and high-frequency metrics. In fact\, the t
 echniques used to address two impulsive waves by Luk and Rodnianski have f
 ound spectacular applications to all the above-mentioned problems.\n\nHowe
 ver\, the case where three or more impulsive waves interact transversally 
 is not covered by earlier work. The methods of Luk-Rodnianski do not apply
  in this case and one conjecturally expects a qualitatively different beha
 viour. I will present a new local existence and stability result for U(1) 
 polarised Cauchy data featuring three impulsive gravitational waves of sma
 ll amplitude propagating towards each other. This result establishes a fra
 mework to subsequently understand the non-linear singularity of three wave
 s\, and eventually the scattering of more singular solutions.\n\nThis is j
 oint work with Jonathan Luk.
LOCATION:Pavilion B Potter Room (B1.19)
END:VEVENT
END:VCALENDAR