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SUMMARY:A new theory of the universe - Neil Turok\, University of Edinburg
 h
DTSTART:20230303T113000Z
DTEND:20230303T123000Z
UID:TALK197536@talks.cam.ac.uk
CONTACT:Alison Wilson
DESCRIPTION:Observations of the universe on very small and large scales ha
 ve revealed a surprising economy in its basic laws and structure. In this 
 light\, we have attempted to find new\, far more minimal solution to cosmo
 logy’s central puzzles. Instead of postulating a pre-hot big bang period
  such as inflation\, we extrapolate the observed universe all the way back
  to the singularity. Instead of adding new particles and forces\, we assum
 e only the Standard Model (including right handed neutrinos) and improve i
 t to maintain local scale symmetry. With this improvement\, the hot plasma
  does not “see” space shrink away at the bang\, which becomes a kind o
 f mirror. The simplest-yet proposed dark matter candidate -- a stable\, ri
 ght handed neutrino -- is then viable.  We calculate the gravitational ent
 ropy for realistic cosmologies\, with radiation\, matter\, lambda and spac
 e curvature and find it favours flat\, homogeneous and isotropic universes
  like ours\, with a small positive cosmological constant. Recently\, we ha
 ve also computed the primordial fluctuations in terms of Standard Model co
 uplings. Subject to a couple of key assumptions\, the amplitude and spectr
 al tilt agree with the observed values\, with no free parameters. (See arX
 iv:2302.00344 and references therein). In principle\, all features of the 
 LCDM model are thereby explained without requiring inflation or any new pa
 rticles. I'll also briefly discuss future observational tests. 
LOCATION:Hoyle Lecture Theatre and online (details to be sent by e-mail)
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