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SUMMARY:Resolving the Hubble tension with emergent dark radiation in unita
 ry gravity - Will Barker
DTSTART:20200115T110000Z
DTEND:20200115T113000Z
UID:TALK138457@talks.cam.ac.uk
CONTACT:Will Handley
DESCRIPTION:We propose a one-parameter extension to LCDM\, expected to str
 ongly affect cosmological tensions.\nAn effective dark radiation component
  in the early universe redshifts away as hot dark matter\,\nthen quintesse
 nce\, leaving a falsifiable cosmic torsion field in the current epoch. Our
  modified\ngravity is a new Poincare gauge theory\, foremost among the 33 
 theories recently found\nalgorithmically to be both power-counting renorma
 lisable and free from ghosts and tachyons. To\nobtain it\, we systematical
 ly chart the cosmologies of these new theories\, as special cases of the\n
 most general parity-preserving\, Ostrogradsky-stable theory with a Yang-Mi
 lls action. As well as\nthe massless 2+ graviton\, our theory may contain 
 a massive 0- graviton. The flat Friedmann\nequations are emergent for any 
 spatial curvature (k-screening)\, with tension-resolving freedom at\nthe s
 cale-invariant epoch that reliably attracts away to modern LCDM evolution.
  We close with\nupcoming Hamiltonian analysis\, COSMOMC validation and sol
 ar system tests.
LOCATION:Battcock Tea area
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