A new mechanism for non-locality from string theory: UV-IR quantum entanglement and its imprints on the CMB

Puff field theories (PFT) arise as the decoupling limits of D3 branes in a Melvin universe and exhibit spatially non-local dynamics. Unlike other realizations of non-locality in string theory, PFTs have full SO(3) rotational symmetry. In this work, we analyze the strongly coupled regime of a PFT through gravitational holography. We find a novel mechanism at the heart of the phenomenon of non-locality: a quantum entanglement of UV and IR dynamics. In the holographic bulk, this translates to an apparent horizon splitting the space into two regions - with the UV completion of the PFT sitting at the horizon. We unravel this intricate UV-IR setting and devise a prescription for computing correlators that extends the original dictionary of holographic renormalization group. We then implement a cosmological scenario where PFT correlators set the initial conditions for primordial fluctuations. We compute the associated power spectrum of the CMB and find that the scenario allows for a distinct stringy signature.