Effective field theory of non-attractor inflation

We study the dynamics of inflation driven by an adiabatic self-gravitating medium, extending the previous works on fluid and solid inflation. Such a class of media comprise perfect fluids, zero and finite temperature solids. By using an effective theory description, we compute the power spectrum for the scalar curvature perturbation ζ of constant energy density hypersurface and the comoving scalar curvature perturbation R in the case of slow-roll, super slow-roll and w-media inflation, an inflationary phase with w constant and −1 < w < −1/3. A similar computation is done for the tensor modes. Such a media are characterised by intrinsic entropy perturbations that can give a significant contribution to the power spectrum and can be used to generate the required seed to primordial black holes. In general the Weinberg theorem is violated; thus on super horizon scale neither ζ nor R are conserved and moreover ζ = R; reheating becomes crucial to predict the spectrum of primordial perturbations. We discuss in detail the physical consequence of such a violation.

Section: Extended Fluid Inflationmentioning

confidence: 83%

Adiabatic media inflation

Celoria

Comelli

Pilo

et al. 2019

“…They can lead to blue spectrum in the tensor sector, and can induce nonvanishing anisotropic stress in the scalar sector that violates the conservation of the curvature perturbation on large scales. See also [22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Breaking discrete symmetries in the effective field theory of inflation

Cannone

Gong

Tasinato

2015

We study the phenomenon of discrete symmetry breaking during the inflationary epoch, using a model-independent approach based on the effective field theory of inflation. We work in a context where both time reparameterization symmetry and spatial diffeomorphism invariance can be broken during inflation. We determine the leading derivative operators in the quadratic action for fluctuations that break parity and time-reversal. Within suitable approximations, we study their consequences for the dynamics of linearized fluctuations. Both in the scalar and tensor sectors, we show that such operators can lead to new direction-dependent phases for the modes involved. They do not affect the power spectra, but can have consequences for higher correlation functions. Moreover, a small quadrupole contribution to the sound speed can be generated.

“…Thus, the Weinberg theorem is violated when η < −3 see [36,37,38,39,40]. Finally, in the case of constant sound speed, namely c 2 s = w =constant, we get (after a suitable redefinition of the integration constants)…”

Section: Dynamics Of R and ζ And The Weinberg Theoremmentioning

confidence: 86%

Intrinsic entropy perturbations from the dark sector

Celoria

Comelli

Pilo

2018

Perfect fluids are modeled by using an effective field theory approach which naturally gives a selfconsistent and unambiguous description of the intrinsic non-adiabatic contribution to pressure variations. We study the impact of intrinsic entropy perturbation on the superhorizon dynamics of the curvature perturbation R in the dark sector. The dark sector, made of dark matter and dark energy is described as a single perfect fluid. The non-perturbative vorticity's dynamics and the Weinberg theorem violation for perfect fluids are also studied.