University of Cambridge > > DAMTP Friday GR Seminar > Resolving the Hubble tension with emergent dark radiation in unitary gravity

Resolving the Hubble tension with emergent dark radiation in unitary gravity

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact Nathan Johnson-McDaniel.

We propose a one-parameter extension to ΛCDM, expected to strongly affect cosmological tensions. An effective dark radiation component in the early universe redshifts away as hot dark matter, then quintessence, leaving a falsifiable cosmic torsion field in the current epoch. Our modified gravity is a new Poincaré gauge theory (PGT), foremost among the 33 PGTs recently found algorithmically to be both power-counting renormalisable and free from ghosts and tachyons. To obtain it, we systematically chart the cosmologies of these new PGTs, as special cases of the most general parity-preserving, Ostrogradsky-stable PGT with a Yang-Mills action. As well as the massless 2+ graviton, our theory may contain a massive 0- graviton. The flat Friedmann equations are emergent for any spatial curvature (k-screening), with tension-resolving freedom at the scale-invariant epoch that reliably attracts away to modern ΛCDM evolution. Ongoing work maps the PGT to an equivalent `extended’ Weyl gauge theory (eWGT) and even a metrical Galileon counterpart. We close with upcoming Hamiltonian analysis, COSMOMC validation and solar system tests.

This talk is part of the DAMTP Friday GR Seminar series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.


© 2006-2024, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity