Breaking of Spatial Diffeomorphism Invariance, Inflation and the Spectrum of Cosmological Perturbations

Understand

Standard inflationary models yield a characteristic signature of a primordial power spectrum with a red tensor and scalar tilt.

• Nevertheless, Cannone et al recently suggested that, by breaking the assumption of spatial diffeomorphism invariance in the context of the effective field theory of inflation, a blue tensor spectrum can be achieved without violating the Null Energy Condition.
• In this context, we explore in which cases a blue tensor tilt can be obtained along with a red tilt in the scalar spectrum.
• Ultimately, we analyze under which conditions this model can reproduce the specific consistency relation of String Gas Cosmology.