Graviton non-Gaussianities and parity violation in the EFT of inflation

Bordin, Lorenzo; Cabass, Giovanni

doi:10.1088/1475-7516/2020/07/014

Cited by 43 publications

(62 citation statements)

References 39 publications

(66 reference statements)

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“…( 72) we see that f γ NL is smaller than f NL by a factor of slow-roll parameter . However, f γ NL,loc is larger than its counterpart coming from the gravitational vacuum fluctuations [62,63,64,65]. A similar result is obtained if one considers some spectator gauge fields [31].…”

Section: Gravitational Waves γγγsupporting

confidence: 67%

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Inflation with multiple vector fields and non-Gaussianities

Gorji,

Mansoori,

Firouzjahi

2020

Preprint

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We consider a model of inflation consisting a triplet of U (1) vector fields with the parity violating interaction which is non-minimally coupled to inflaton. The vector field sector enjoys global O(3) symmetry which admits isotropic configuration and provides not only vector modes but also scalar and tensor modes. We decompose the scalar perturbations into the adiabatic, entropy and isocurvature perturbations and compute all power spectra and cross correlations of the scalar and the tensor sectors. The tensor modes associated with the vector fields contribute to the power spectrum of gravitational waves while the parity violating term generates chirality in gravitational power spectra and bispectra. We study nonlinear scalar and tensor perturbations and compute all bispectra and three-point crosscorrelations. In particular, it is shown that the non-Gaussianity of curvature perturbations and gravitational waves are enhanced by the vector field perturbations. We show that non-Gaussianities put strong constraints on the model parameters such as the parity violating coupling and the fractional energy of the vector fields.

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Section: Gravitational Waves γγγsupporting

confidence: 67%

“…Summing the above corrections, the power spectrum of the tensor perturbations associated with the vector fields perturbations to leading order becomes Eq. (65).…”

Section: C22 T Tmentioning

confidence: 99%

Inflation with multiple vector fields and non-Gaussianities

Gorji,

Mansoori,

Firouzjahi

2020

Preprint

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“…This is true even though we allow for boost breaking interactions. This is a particular case of a more general set of results obtained in [59][60][61], where it was also concluded that the first boost breaking ψ φφγ generated from coupling to the inflaton foliation of time comes at three-derivatives. In that work the authors work at the level of the Lagrangian and use field redefinitions to remove redundant couplings in the EFT of inflation.…”

Section: A Massless Scalar Coupled To Gravitymentioning

confidence: 73%

“…• It would be interesting to investigate the extent to which our bootstrap approach can remove redundancies in the EFT of inflation. This has been considered in [59][60][61] at the level of the Lagrangian where field redefinitions were used to remove redundant interactions. Our on-shell approach should make this process particularly simple and transparent.…”

Section: Summary and Future Directionsmentioning

confidence: 99%

From locality and unitarity to cosmological correlators

Jazayeri

Pajer

Stefanyszyn

2021

J. High Energ. Phys.

118

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In the standard approach to deriving inflationary predictions, we evolve a vacuum state in time according to the rules of a given model. Since the only observables are the future values of correlators and not their time evolution, this brings about a large degeneracy: a vast number of different models are mapped to the same minute number of observables. Furthermore, due to the lack of time-translation invariance, even tree-level calculations require an increasing number of nested integrals that quickly become intractable. Here we ask how much of the final observables can be “bootstrapped” directly from locality, unitarity and symmetries.To this end, we introduce two new “boostless” bootstrap tools to efficiently compute tree-level cosmological correlators/wavefunctions without any assumption about de Sitter boosts. The first is a Manifestly Local Test (MLT) that any n-point (wave)function of massless scalars or gravitons must satisfy if it is to arise from a manifestly local theory. When combined with a sub-set of the recently proposed Bootstrap Rules, this allows us to compute explicitly all bispectra to all orders in derivatives for a single scalar. Since we don’t invoke soft theorems, this can also be extended to multi-field inflation. The second is a partial energy recursion relation that allows us to compute exchange correlators. Combining a bespoke complex shift of the partial energies with Cauchy’s integral theorem and the Cosmological Optical Theorem, we fix exchange correlators up to a boundary term. The latter can be determined up to contact interactions using unitarity and manifest locality. As an illustration, we use these tools to bootstrap scalar inflationary trispectra due to graviton exchange and inflaton self-interactions.

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“…Graviton non-Gaussianities in single-clock inflation have been investigated in detail in [11,22]. What happens when couplings with the foliation are included has been discussed in [23,24,25,26]. How do we extend the analysis to different symmetry breaking patterns?…”

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confidence: 99%

Zoology of Graviton non-Gaussianities

Cabass

2021

Preprint

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We characterize graviton non-Gaussianities in models of inflation where de Sitter boosts are spontaneously broken. We discuss which of the symmetry breaking patterns studied in Nicolis et al., 2015 [1] can sustain a period of quasi de Sitter expansion, and show that the symmetry breaking pattern of Solid Inflation allows the most freedom for graviton interactions. We comment on the phenomenological consequences of some of these interactions. As a byproduct of this analysis we construct the "EFT of Solid Inflation", which has all the useful features of the EFT of Inflation but for the case of broken spatial diffeomorphisms.

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Graviton non-Gaussianities and parity violation in the EFT of inflation

Cited by 43 publications

References 39 publications

Inflation with multiple vector fields and non-Gaussianities

Inflation with multiple vector fields and non-Gaussianities

From locality and unitarity to cosmological correlators

Zoology of Graviton non-Gaussianities

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