Read Cosmology in Ten Minutes:
Or on HN:
The many-universe idea has been around for quite a while. They must have added something interesting. The anisotropy is probably pretty significant.
which was submitted to PRL by those authors two days ago.
I'm a physicist, but not an astrophysicist or cosmologist, so I'm having trouble making head or tails of it. But most of the highly speculative stuff in the article isn't mentioned in the paper.
"Detailed measurements made by the satellite have shown that the fluctuations in the microwave background are about 10% stronger on one side of the sky than those on the other.
Sean Carroll conceded that this might just be a coincidence, but pointed out that a natural explanation for this discrepancy would be if it represented a structure inherited from our universe's parent."