How solid is the BICEP2 B-mode result?

Another wordpress post about BICEP2 – by astrophysicist Phil Bull – with some comments on possible issues with the data…

Lumps 'n' Bumps

Phew! An exciting day indeed, so I’ll jot down a few notes to recap what happened.

The BICEP2/Keck experiments detected B-modes at large angular scales in the polarisation of the CMB. They released two papers and some data online just as the announcement was made, which you can find here. Not all of the data mind, but it’s plenty to go on for now.

Their interpretation of the data is that they detect a bump at low-ell that is characteristic of primordial B-modes generated by inflation. If true, this is super exciting, as it gives us a (sort of, but not really) direct detection of gravitational waves, and opens up a new window on the very early Universe (and hence extremely high energy scales). People are even saying it’s a probe of quantum gravity, which I guess is sort of true. Furthermore, they find a best-fit value of the…

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One Response to “How solid is the BICEP2 B-mode result?”

  1. […] A number of cosmologists have given their (more technical) opinions and interpretations online: Peter Coles at Sussex, Phil Bull in Oslo, and I’ll add a few more as I find them. 18/03: this from Renée Hlozek at Princeton,  more from Peter Coles, […]

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