My latest paper with Avi Loeb has just been accepted for publication in ApJ Letters! I can confidently say that is at the same time one of the simplest yet most exciting papers I have ever written (Avi is really good at coming up with simple yet profound ideas, and I won’t lie, the idea behind this paper is entirely his). The short idea is that one can (with some caveats) rule out the whole inflationary paradigm, without reference to any specific model, by finding a background of relic gravitons with certain specific properties, the reason being that inflation should have washed it out: we show that this will be extremely challenging, but not impossible (I will likely have retired by the time it will even be possible). You can find the preprint version of the paper, which is also the first one I have written with my new Trento affiliation, on arXiv: 2208.14088.
