Two-point correlators revisited: Separating fast and slow scales in multifield models of inflation
Andrei Frolov (SFU)
May 05, 2016
Abstract: In the era of precision cosmological observations and complicated models of inflation, calculating primordial fluctuation spectrum is a chore that needs to be done over and over again. Slow-roll approximation is no longer adequate for many models, and the usual brute-force numerical method of tracing fluctuation mode from Minkowski vacuum to horizon crossing and freezout is very inefficient, as it has to trace every single oscillation deep within horizon. In this talk I present a new method to calculate primordial fluctuation spectra, which is based on tracing evolution of Cholesky-decomposed field correlators rather than field modes themselves. This effectively separates slow and fast scales of quantum fluctuation during inflation, and allows extremely precise calculations of spectra at vastly improved efficiency.