I was reading a post earlier from Peter Woit's Not Even Wrong blog and came across the following reference to the paper "What if string theory has no de Sitter vacua?" by Ulf H. Danielsson, Thomas Van Riet. The preprint is on the Arxiv here - it isn't clear if it has been published in a refereed journal.
From this analysis we conclude that string theory has not made much progress on the problem of the cosmological constant during the last 15 years. There is a general agreement that the presence of dark energy should be an important clue to new physics. So far, string theory has not been up to the challenge. Or to be more precise, string theorists have not been up to the challenge.
From what we have seen so far, we believe that the most sensible attitude is to accept there are no dS vacua at all because string theory conspires against dS vacua.
The suggestion here is basically that effective field theories on a deSitter background are in the Swampland, so can’t be derived from string theory. Since we seem to live in a deSitter space, the obvious conclusion to draw from this is that string theory is falsified: it can’t be the fundamental theory we are looking for. The authors discuss various unconvincing ways to try and avoid this conclusion.
Now I'm well aware that Woit really, really doesn't seem to like String Theory. That being said, the books/papers/videos I've come across over basically my entire life seem to showcase the radical potential for the theory to help us understand the most foundational aspects of our world (replicate standard model, combine quantum mechanics and general relatively, etc.), so this would be pretty shocking to me.
Can anyone explain what might be going on here? Any input is appreciated...