This should hold up, I've already checked out the paper... the science is there, unless they are flat out lying about their experimental data. I would like to emphasize that this is not a "direct detection" of gravitational waves. This is detecting an artifact of (primordial) gravitational waves, which is almost as good, but should only serve to justify LISA and future generations of gravitational wave detectors. As the article states, this does absolutely confirm inflation, and is a major victory of cosmology. Also, this doesn't necessarily confirm or nix the multiverse theory, that's something still shelved in the category of "unknowables", at least with today's technology and physics. It's an exciting time to be alive, but we're not done. :)
Does this finding confirm any specific theory of inflation? Also, pending confirmation from Planck, what would you say is the next logical step in advancing this discovery?
Well, it's a relatively slow day at work (sorry for the delay in response, just got hassled after beginning my response), and the paper is here. I haven't read through the whole thing completely, but the data is solid. It doesn't confirm one specific inflation theory, but constrains the boundaries to a smaller region of inflationary conditions. So there are several variants of inflation that are now known to be false. BICEP, the main telescope that gathered the data their premise is built on, looks at one swath of sky, about 20 x 20 degrees. If we built a similar telescope and stared somewhere else, that should further constrain the known conditions of inflation, and the longer you gather a dataset, it will further constrain the limits. A telescope with these capabilities in space would also eliminate some of the noise floor, but there are some huge engineering challenges to overcome before we could launch some type of BICEP analogue. Edit/Disclaimer: I don't work in cosmology, and I've only taken one General Relativity class, but will gladly field questions, and accept objection. :)