BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Three-Dimensional Quantum Bubble Collisions - Jonathan Braden
DTSTART:20150608T120000Z
DTEND:20150608T130000Z
UID:TALK59239@talks.cam.ac.uk
CONTACT:33215
DESCRIPTION:Title : Three-Dimensional Quantum Bubble Collisions\n\nAbstrac
 t :\nFirst-order phase transitions proceed through the nucleation and subs
 equent collision of bubbles.  In inflationary multiverse scenarios based o
 n false vacuum eternal inflation\, such collision events are believed to b
 e ubiquitous and provide a possible avenue to observationally test the mul
 tiverse framework.  They also play an important role in any early high tem
 perature phase transitions that may have occurred within our local Hubble 
 patch.\n\nI will present results for full three-dimensional collisions bet
 ween pairs of bubbles\, including for the first time the effects of (initi
 ally small) quantum fluctuations.  In the standard treatment of pairwise c
 ollisions\, the field profile is assumed to possess SO(2\,1) spatial symme
 try which reduces the dynamics to a single spatial dimension.  Although th
 is profile describes the most likely field configuration\, quantum fluctua
 tions do not respect the symmetries.  Therefore\, the fluctuations require
  a fully three-dimensional approach.  I will show that for a wide class of
  potentials\, the collision dynamics initially drives a linear parametric 
 instability in the fluctuations\, causing them to grow exponentially in ti
 me.  This process is a spatially inhomogeneous version of Bogoliubov parti
 cle production.  Once the fluctuations become sufficiently large\, mode-mo
 de coupling leads to a complete breakdown of the SO(2\,1) symmetry.  The b
 ubble walls in the collision region dissolve and a population of localized
  oscillating blobs of field known as oscillons are formed.  This has possi
 ble implications for the production of gravitational waves or black holes 
 during bubble collisions.
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
END:VEVENT
END:VCALENDAR