Fotis Koutroulis: Thermal effects in Ising Cosmology

Thursday 8 Dec 2022, 11:15 → 12:15 Europe/Ljubljana

https://zoom.us/j/3601731049?pwd=bVNQRjUxU2ExZ0cveWcxYXNUUGdjZz09 (Zoom)

Abstract:
We consider a real scalar field in de Sitter background and compute its thermal propagators. Using arguments from holography we propose, in a dS/CFT context, that non-trivial thermal effects as seen by an ‘out’ observer can be encoded in the anomalous dimensions of the d = 3 Ising model. One of these anomalous dimensions, the critical exponent η, fixes completely a number of cosmological observables and is almost entirely responsible for the deviation of the cosmological spectral index nS of scalar fluctuations from unity.
A connection with standard Inflation may be possible at the late time regimes where the time-dependent part of the field dominates.