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SUMMARY:Horizons and Tunneling in the Euclidean False Vacuum - Kate Marvel
  (DAMTP)
DTSTART:20071102T130000Z
DTEND:20071102T140000Z
UID:TALK8269@talks.cam.ac.uk
CONTACT:David Seery
DESCRIPTION:In the thin-wall approximation\, the decay of a gravitating fa
 lse vacuum to a lower-energy state is affected by the cosmological horizon
  structure in both spaces.  I show that the nucleation radius of a bubble 
 of true vacuum depends on the surface tension of its boundary.  This radiu
 s equals the false vacuum cosmological horizon at a critical tension\, bey
 ond which a tunneling instanton solution does not exist.  I therefore argu
 e that there is a bound on allowed membrane tension in theories which rely
  on semiclassical tunneling to relax the cosmological constant.
LOCATION:Pavilion B Meeting Room 9
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