Maria

Paper day: we (Danielle Dineen, Rich Holman and Greg Kaplanek) finally got the complete leading calculation of how primordial fluctuations decohere due to their gravitational interactions with an environment of unobserved short wavelength modes during inflation. The result naively breaks down at late times but we show how it can be systematically resummed to extend the predictions to the end of inflation. There are a few surprises: The result is *not* slow roll suppressed and so is bigger than preliminary partial calculations had indicated. The lack of suppression is only seen once *both* tensor and scalar environments are considered together, and missed if they are treated separately. This key observation was Rich’s insight. arxiv.org/abs/2607.22914

This came out the other day. It argues that relaxation mechanisms aimed at the cosmological constant problems are likely to undermine many mainstream takes on cosmology (using the QCD axion as an example). But they need not also undermine all other physics that uses a scalar potential (eg Higgs physics), contrary to what is sometimes claimed.