scholarly journals Primordial non-Gaussianity in supersolid inflation

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Marco Celoria ◽  
Denis Comelli ◽  
Luigi Pilo ◽  
Rocco Rollo
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Secondary Production ◽  
Scalar Fields ◽  
Effective Field ◽  
Spontaneous Breaking ◽  
Slow Roll ◽  
Angular Average ◽  
Scalar Sector ◽  
Scalar Perturbations

Abstract We study primordial non-gaussianity in supersolid inflation. The dynamics of supersolid is formulated in terms of an effective field theory based on four scalar fields with a shift symmetric action minimally coupled with gravity. In the scalar sector, there are two phonon-like excitations with a kinetic mixing stemming from the completely spontaneous breaking of diffeomorphism. In a squeezed configuration, fNL of scalar perturbations is angle dependent and not proportional to slow-roll parameters showing a blunt violation of the Maldacena consistency relation. Contrary to solid inflation, the violation persists even after an angular average and generically the amount of non-gaussianity is significant. During inflation, non-gaussianity in the TSS and TTS sector is enhanced in the same region of the parameters space where the secondary production of gravitational waves is sizeable enough to enter in the sensitivity region of LISA, while the scalar fNL is still within the current experimental limits.

scholarly journals Inflationary perturbation spectra at next-to-leading slow-roll order in effective field theory of inflation

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Guang-Hua Ding ◽  
Jin Qiao ◽  
Qiang Wu ◽  
Tao Zhu ◽  
Anzhong Wang
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
High Energy Physics ◽  
Power Spectra ◽  
High Energy ◽  
Effective Field ◽  
Spectral Indices ◽  
Leading Order ◽  
Slow Roll ◽  
Tensor Perturbations

AbstractThe effective field theory (EFT) of inflation provides an essential picture to explore the effects of the unknown high energy physics in the single scalar field inflation models. For a generic EFT of inflation, possible high energy corrections to simple slow-roll inflation can modify both the propagating speed and dispersion relations of the cosmological scalar and tensor perturbations. With the arrival of the era of precision cosmology, it is expected that these high energy corrections become more important and have to be taken into account in the analysis with future precise observational data. In this paper we study the observational predictions of the EFT of inflation by using the third-order uniform asymptotic approximation method. We calculate explicitly the primordial power spectra, spectral indices, running of the spectral indices for both scalar and tensor perturbations, and the ratio between tensor and scalar spectra. These expressions are all written in terms of the Hubble flow parameters and the flow of four new slow-roll parameters and expanded up to the next-to-leading order in the slow-roll expansions so they represent the most accurate results obtained so far in the literature. The flow of the four new slow-roll parameters, which arise from the four new operators introduced in the action of the EFT of inflation, can affect the primordial perturbation spectra at the leading-order and the corresponding spectral indices at the next-to-leading order.

scholarly journals Cosmic Microwave Background from Effective Field Theory †

Universe ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 155
Author(s):  
Sayantan Choudhury
Keyword(s):  
Field Theory ◽  
Cosmic Microwave Background ◽  
Effective Field Theory ◽  
Vacuum State ◽  
Effective Field ◽  
De Sitter ◽  
Microwave Background ◽  
Slow Roll ◽  
Point Correlation ◽  
Single Field

In this work, we study the key role of generic Effective Field Theory (EFT) framework to quantify the correlation functions in a quasi de Sitter background for an arbitrary initial choice of the quantum vacuum state. We perform the computation in unitary gauge, in which we apply the St u ¨ ckelberg trick in lowest dimensional EFT operators which are broken under time diffeomorphism. In particular, using this non-linear realization of broken time diffeomorphism and truncating the action by considering the contribution from two derivative terms in the metric, we compute the two-point and three-point correlations from scalar perturbations and two-point correlation from tensor perturbations to quantify the quantum fluctuations observed in the Cosmic Microwave Background (CMB) map. We also use equilateral limit and squeezed limit configurations for the scalar three-point correlations in Fourier space. To give future predictions from EFT setup and to check the consistency of our derived results for correlations, we use the results obtained from all classes of the canonical single-field and general single-field P ( X , ϕ ) model. This analysis helps us to fix the coefficients of the relevant operators in EFT in terms of the slow-roll parameters and effective sound speed. Finally, using CMB observations from Planck we constrain all these coefficients of EFT operators for the single-field slow-roll inflationary paradigm.

scholarly journals Prospects for primordial gravitational waves in string inflation

2016 ◽  
Vol 25 (12) ◽  
pp. 1644011 ◽  
Author(s):  
Susha L. Parameswaran ◽  
Ivonne Zavala
Keyword(s):  
Field Theory ◽  
String Theory ◽  
Gravitational Waves ◽  
Effective Field Theory ◽  
Effective Field ◽  
Moduli Stabilization ◽  
Slow Roll ◽  
Primordial Gravitational Waves ◽  
Difficult Challenge ◽  
String Models

Assuming that the early universe had (i) a description using perturbative string theory and its field theory limit, (ii) an epoch of slow-roll inflation within a four-dimensional effective field theory and a hierarchy of scales [Formula: see text] that keeps the latter under control, we derive an upper bound on the amplitude of primordial gravitational waves. The bound is very sensitive to mild changes in numerical coefficients and the expansion parameters. For example, allowing couplings and mass-squared hierarchies [Formula: see text] implies [Formula: see text], but asking more safely for hierarchies [Formula: see text], the bound becomes [Formula: see text]. Moreover, large volumes — typically used in string models to keep backreaction and moduli stabilization under control — drive [Formula: see text] down. Consequently, any detection of inflationary gravitational waves would present an interesting but difficult challenge for string theory.

scholarly journals Testing Screened Modified Gravity

Universe ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 11
Author(s):  
Philippe Brax ◽  
Santiago Casas ◽  
Harry Desmond ◽  
Benjamin Elder
Keyword(s):  
Field Theory ◽  
Solar System ◽  
Long Range ◽  
Effective Field Theory ◽  
Modified Gravity ◽  
Scalar Fields ◽  
Short Review ◽  
Effective Field ◽  
Point Of View ◽  
Theory Point

Long range scalar fields with a coupling to matter appear to violate known bounds on gravitation in the solar system and the laboratory. This is evaded thanks to screening mechanisms. In this short review, we shall present the various screening mechanisms from an effective field theory point of view. We then investigate how they can and will be tested in the laboratory and on astrophysical and cosmological scales.

scholarly journals Spontaneous Lorentz Violation from Infrared Gravity

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1854
Author(s):  
Fabrizio Illuminati ◽  
Gaetano Lambiase ◽  
Luciano Petruzziello
Keyword(s):  
Field Theory ◽  
Uncertainty Principle ◽  
Effective Field Theory ◽  
Effective Field ◽  
Spontaneous Breaking ◽  
Uncertainty Relations ◽  
Standard Model Extension ◽  
Heisenberg Uncertainty Principle ◽  
Stringent Constraint ◽  
Heisenberg Uncertainty

In this paper, we investigate a novel implication of the non-negligible spacetime curvature at large distances when its effects are expressed in terms of a suitably modified form of the Heisenberg uncertainty relations. Specifically, we establish a one-to-one correspondence between this modified uncertainty principle and the Standard Model Extension (SME), a string-theoretical effective field theory that accounts for both explicit and spontaneous breaking of Lorentz symmetry. This tight correspondence between string-derived effective field theory and modified quantum mechanics with extended uncertainty relations is validated by comparing the predictions concerning a deformed Hawking temperature derived from the two models. Moreover, starting from the experimental bounds on the gravity sector of the SME, we derive the most stringent constraint achieved so far on the value of the free parameter in the extended Heisenberg uncertainty principle.

scholarly journals Two interacting scalars system in curved spacetime — vacuum stability from the curved spacetime Effective Field Theory (cEFT) perspective

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Zygmunt Lalak ◽  
Anna Nakonieczna ◽  
Łukasz Nakonieczny
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Field Potential ◽  
Scalar Fields ◽  
Effective Field ◽  
Kinetic Term ◽  
Curved Spacetime ◽  
Minimal Coupling ◽  
Vacuum Stability ◽  
Higher Dimensional

Abstract In this article we investigated the influence of the gravity mediated higher dimensional operators on the issue of vacuum stability in a model containing two interacting scalar fields. As a framework we used the curved spacetime Effective Field Theory (cEFT) applied to the aforementioned system in which one of the scalars is heavy. After integrating out the heavy scalar we used the standard Euclidean approach to the obtained cEFT. Apart from analyzing the influence of standard operators like the non-minimal coupling to gravity and the dimension six contribution to the scalar field potential, we also investigated the rarely discussed dimension six contribution to the kinetic term and the new gravity mediated contribution to the scalar quartic self-interaction.

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