Intrinsic entropy perturbations from the dark sector

Celoria, Marco; Comelli, Denis; Pilo, Luigi

doi:10.1088/1475-7516/2018/03/027

Cited by 11 publications

(22 citation statements)

References 51 publications

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“…The total, improved transformation is then 11) to lowest order in ζ, and it is straightforward to check that (5.11) is a symmetry of (5.8) and, correspondingly, that the associated ζ k profile solves the equations of motion stemming from (5.8).…”

Section: Shift Symmetric Adiabatic Modementioning

confidence: 99%

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The effective theory of shift-symmetric cosmologies

Finelli

Goon

Pajer

et al. 2018

J. Cosmol. Astropart. Phys.

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A shift symmetry is a ubiquitous ingredient in inflationary models, both in effective constructions and in UV-finite embeddings such as string theory. It has also been proposed to play a key role in certain Dark Energy and Dark Matter models. Despite the crucial role it plays in cosmology, the observable, model independent consequences of a shift symmetry are yet unknown. Here, assuming an exact shift symmetry, we derive these consequences for single-clock cosmologies within the framework of the Effective Field Theory of Inflation. We find an infinite set of relations among the otherwise arbitrary effective coefficients, which relate non-Gaussianity to their time dependence. For example, to leading order in derivatives, these relations reduce the infinitely many free functions in the theory to just a single one. Our Effective Theory of shift-symmetric cosmologies describes, among other systems, perfect and imperfect superfluids coupled to gravity and driven superfluids in the decoupling limit. Our results are the first step to determine observationally whether a shift symmetry is at play in the laws of nature and whether it is broken by quantum gravity effects. * b.finelli@uu.nl † g.l.goon@uu.nl ‡ E.Pajer@uu.nl § l.santoni@uu.nl

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Section: Shift Symmetric Adiabatic Modementioning

confidence: 99%

“…Also, shift symmetric models have been proposed to model both Dark Matter (see e.g. [9]) and Dark Energy [10,11]. Since our analysis is general to any FLRW spacetime, it can be used to study not just inflation but these other cosmological phases as well.…”

Section: Introductionmentioning

confidence: 99%

The effective theory of shift-symmetric cosmologies

Finelli

Goon

Pajer

et al. 2018

J. Cosmol. Astropart. Phys.

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“…In radiation domination, at superhorizon scales, the fact that R − ζ = 0 can be encoded via relative difference in density perturbations of the various species and also with intrinsic entropic perturbation for non barotropic species. As matter of fact such contribution can be attributed only to the dark sector [10,30].…”

Section: Slow-rollmentioning

confidence: 99%

Adiabatic media inflation

Celoria

Comelli

Pilo

et al. 2019

J. Cosmol. Astropart. Phys.

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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.

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“…The situation is different for models characterized by different symmetry breaking patterns, featuring more degrees of freedom for which the Weinberg theorem does not hold. In this case, R and ζ are not conserved and R = ζ at superhorizon scales; thus, the details of reheating have to be taken into account [3][4][5][6][7]. That is exactly what happens when a fluid [8] or solid [9] drives inflation.…”

Section: Introductionmentioning

confidence: 99%

Boosting GWs in supersolid inflation

Celoria

Comelli

Pilo

et al. 2021

J. High Energ. Phys.

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102

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Inflation driven by a generic self-gravitating medium is an interesting alternative to study the impact of spontaneous spacetime symmetry breaking during a quasi de-Sitter phase, in particular the 4-dimensional diffeomorphism invariance of GR is spontaneously broken down to I SO(3). The effective description is based on four scalar fields that describe the excitations of a supersolid. There are two phonon-like propagating scalar degrees of freedom that mix non-trivially both at early and late times and, after exiting the horizon, give rise to non-trivial correlations among the different scalar power spectra. The non-linear structure of the theory allows a secondary gravitational waves production during inflation, efficient enough to saturate the present experimental bound and with a blue-tilted spectral index.

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Intrinsic entropy perturbations from the dark sector

Cited by 11 publications

References 51 publications

The effective theory of shift-symmetric cosmologies

The effective theory of shift-symmetric cosmologies

Adiabatic media inflation

Boosting GWs in supersolid inflation

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