Non-Unitary Evolution in the General Extended EFT of Inflation & Excited Initial States

Understand

I study the "general" case that arises in the Extended Effective Field Theory of Inflation (gEEFToI), in which the coefficients of the sixth order polynomial dispersion relation depend on the physical wavelength of the fluctuation mode, hence they are time-dependent.

• At arbitrarily short wavelengths the unitarity is lost for each mode.
• Depending on the values of the gEEFToI parameters in the unitary gauge action, two scenarios can arise: in one, the coefficients of the polynomial become singular, flip signs at some physical wavelength and asymptote to a constant value as the wavelength of the mode is stretched to infinity.
• Starting from the WKB vacuum, the two-point function is essentially singular in the infinite IR limit.