> The astrophysicists, from the University of Cambridge, the University of Trento, and Harvard University, say that there is a clear, unambiguous signal in the cosmos that could eliminate inflation as a possibility.

> “Inflation was theorised to explain various fine-tuning challenges of the so-called hot Big Bang model,” ... “It also explains the origin of structure in our Universe as a result of quantum fluctuations.”

> However, the Big Bang theory does not allow for the existence of the CGB, as it suggests that the exponential inflation of the newborn universe diluted relics such as the CGB to a point that they are undetectable. This can be turned into a test: if the CGB [cosmic graviton background] were detected, clearly this would rule out cosmic inflation, which does not allow for its existence.

https://www.cam.ac.uk/research/news/can-cosmic-inflation-be-ruled-out