Article
Astronomy & Astrophysics
Mehrdad Mirbabayi, Andrei Gruzinov
Summary: Sphaleron heating is proposed as a mechanism for warm inflation when the inflaton is coupled to pure Yang-Mills as an axion. The presence of heating introduces a friction coefficient gamma proportional to T-3 in the inflaton's equation of motion, as well as a thermal contribution to cosmological fluctuations. In the absence of knowledge about the inflaton potential, non-Gaussianity is the most promising approach for detecting the signatures of this model. By extending previous work, we compute the scalar three-point correlation function and identify distinct features in the squeezed and folded limits. As a detection strategy, we find that combining the equilateral template with a new template yields a high overlap with the shape of non-Gaussianity for 0.01 <= gamma/H <= 1000, with 0.7 < |f(NL)| < 50 in this range.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Hemza Azri, Isaac Bamwidhi, Salah Nasri
Summary: This paper explores two-field inflation in the context of purely affine gravity, introducing a covariant formulation that leads to a curved field space allowing for significant departure from purely metric gravity. By allowing specific noncanonical field kinetic terms, the curved field manifold can be flattened, simplifying inflationary dynamics and enabling new predictions.
Article
Astronomy & Astrophysics
Maria Mylova, Marianthi Moschou, Niayesh Afshordi, Joao Magueijo
Summary: This paper introduces a thermal bimetric model and explores its non-Gaussian features, providing precise predictions based on the characteristics of the model. These results are of great significance for future cosmological surveys.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Aliki Litsa, Katherine Freese, Evangelos I. Sfakianakis, Patrick Stengela, Luca Visinellij
Summary: We propose a new way of studying the Higgs potential at extremely high energies by considering the space dependence and non-Gaussianity of the resulting temperature anisotropy spectrum. The observed temperature anisotropies in the Cosmic Microwave Background (CMB) are largely excluded to be primarily caused by Higgs effects. Observational searches for non-Gaussianity in the CMB can be used to constrain the dynamics of the Higgs boson at very high energies.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Emanuela Dimastrogiovanni, Matteo Fasiello, A. Emir Gumrukcuoglu
Summary: This paper investigates the possibility of extra spinning particles during inflation, focusing on the spin-2 case. The study explores the parameter space of the inflationary Lagrangian and identifies regions with signatures detectable by upcoming CMB probes. The analysis reveals the presence of a local-type non-Gaussianity in the gravitational wave spectrum and three-point function, which may be within the sensitivity range of both LiteBIRD and CMB-S4 experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Matthew W. Davies, Pedro Carrilho, David J. Mulryne
Summary: In this study, we work within an idealized framework to match a series of evolution phases defined by the second slow-roll parameter eta. We calculate the reduced bispectrum, f(NL), for inflation models with a significant peak in their primordial power spectra. Our findings show that f(NL) remains relatively constant over the scales where the peak is located, and we provide an analytic approximation for this value. Additionally, we identify the conditions under which f(NL) is large enough to have a significant impact on the production of primordial black holes (PBHs) and scalar induced gravitational waves (SIGWs). The analytic formulas for the gradient of the rise and fall in the power spectrum, along with these findings, offer a toolkit for designing or quickly analyzing inflationary models that generate PBHs and SIGWs.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Amjad Ashoorioon, Ghazal Geshnizjani, Hyung J. Kim
Summary: In this paper, we study the validity and non-Gaussianity of Extended Effective Field Theory of Inflation (EEFToI) with initial conditions set with dispersion relations omega(2) a k(6). By computing the bispectrum and investigating the shape of triangles, we find interesting regions of parameter space where EEFToI with these initial conditions is sensible.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Lei-Hua Liu, Bin Liang, Ya-Chen Zhou, Xiao-Dan Liu, Wu-Long Xu, Ai-Chen Li
Summary: The study on the non-Gaussianity of canonical curvaton scenario using a generalized delta N formalism reveals that most parameter spaces are consistent with observational constraints. The research shows that the well-known parameter values can be accurately recovered in the absence of nonlinear evolution.
Article
Astronomy & Astrophysics
Philip Clarke, E. P. S. Shellard
Summary: The study proposes a practical numerical method for calculating the primordial bispectrum of different inflation models by utilizing an augmented Legendre polynomial basis. The method allows for fast and accurate computation of coefficients, marking a significant advancement in directly confronting inflation models during observational pipelines.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Philippe Brax, Andrei Lazanu
Summary: DHOST inflation models with deviations from a pure de Sitter background induced by an axion-like potential can result in large non-Gaussianities. We investigate the characteristics of non-Gaussianities in these models and compare them to the findings of the Planck experiment. The overlap between DHOST non-Gaussianities and the equilateral, orthogonal, and local templates can be arbitrarily small, but this does not rule out the possibility of DHOST models exhibiting large non-Gaussianities.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Parviz Goodarzi
Summary: This work investigates the mechanism of gravitational baryogenesis in the framework of the non-minimal derivative coupling model. It is shown that the baryon asymmetry can be generated at both low and high reheating temperatures through the coupling between the derivative of the Ricci scalar curvature and the baryon current.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Dhiraj Kumar Hazra, Daniela Paoletti, Ivan Debono, Arman Shafieloo, George F. Smoot, Alexei A. Starobinsky
Summary: In this study, constraints on inflationary dynamics and features in the primordial power spectrum of scalar perturbations are presented using Cosmic Microwave Background temperature and polarization data from Planck 2018 data release. Models with suppression and oscillatory features are analyzed and compared with baseline slow-roll potentials. The significance of sharp features has decreased compared to previous data analysis, and bispectra are computed for the best fit candidates obtained from the analysis.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
M. AlHallak, N. Chamoun, M. S. Eldaher
Summary: The study of Natural Inflation with non-minimal coupling to gravity in the context of extended gravity shows a significant improvement in the compatibility between theoretical results and observational constraints.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
R. Rakhi, Minu Joy
Summary: This study examines an inflationary model propelled by a scalar field with a potential featuring a step in the second derivative with respect to the field. The 3-point function and non-Gaussianity associated with this model are calculated for the best-fit potential parameter values, revealing the shape and scale dependence of the 3-point function. The distinctive ringing behavior of f(NL) in this model distinguishes it from previously studied models, with oscillations in fNL lasting for a longer range of k values, potentially allowing for differentiation from models with different potential features.
PRAMANA-JOURNAL OF PHYSICS
(2022)
Article
Astronomy & Astrophysics
Diptimoy Ghosh, Amartya Harsh Singh, Farman Ullah
Summary: We study the analytic structure of in-in correlation functions in a deSitter background to probe the initial conditions for inflation. We emphasize the flexibility of vacuum choices and clarify their role in calculations and diagrammatic interpretation. By considering various possibilities and examining pole structures, such as adding excitations and coherent states, we shed light on the missing details that link quantum and classical initial conditions, and aim to enhance our understanding of in-in correlators in inflation.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Celia Escamilla-Rivera
Summary: In this work, the authors discuss modified and extended cosmological models using current observational tests, particularly focusing on the interpretation of dynamical dark energy by theories like f(R) and f(T, B) based on late universe measurements. Precision cosmostatistics has also emerged as a motivated endeavor to test gravitational physics at cosmic scales, providing a pathway to propose alternative approaches from the standard ΛCDM scenario.
ASTRONOMISCHE NACHRICHTEN
(2021)
Article
Physics, Multidisciplinary
N. M. Jimenez Cruz, Celia Escamilla-Rivera
Summary: This work presents a new generic parameterisation for f (R) theories that can accurately reproduce f (R)-like evolution in late and early universe. The study extends to finding constraints on early universe that satisfy Big Bang Nucleosynthesis data. Additionally, it distinguishes between f (R) scenarios at different routes of the distance ladder, showing potential for modifying gravity at this level.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Astronomy & Astrophysics
M. Corman, Celia Escamilla-Rivera, M. A. Hendry
Summary: The study suggests that late-time acceleration in the universe may result from gravitational leakage into extra dimensions rather than a non-zero cosmological constant. LISA has the potential to probe and constrain the phenomenon of gravitational leakage through observations of gravitational-wave merger events, providing insights into modified gravity models.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Belen Carvente, Victor Jaramillo, Celia Escamilla-Rivera, Dario Nunez
Summary: The paper suggests a model using a complex scalar field to describe dark energy dynamics, which can mimic the behavior of dark energy. However, when applied to current observations, there are constraints that may require further research into alternative models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Celia Escamilla-Rivera, Hernando Quevedo
Summary: Proposing an alternative cosmography using Horava-Lifshitz gravity as a model for quantum gravity, the study suggests that the Universe appears flat classically according to the ΛCDM model, but is actually curved from a quantum perspective. The findings indicate a non-flat scenario and a specific value for the Horava parameter that could be interpreted as a measure of a quantum effect.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
Celia Escamilla-Rivera, Julio C. Fabris
Summary: General Relativity is like an elegant crystal glass, delicate and easily breakable when its principles are touched upon, leading researchers to pursue non-Lagrangian theory as a way to solve existing problems while being aware of the possibility of creating new ones.
Article
Physics, Multidisciplinary
Celia Escamilla-Rivera, Aldo Gamboa
Summary: In this study, we propose a cosmological model based on the holographic principle that allows for an interaction between dark energy and dark matter to explain the accelerated expansion of the universe. By using redshift parameterizations, we obtain an analytical expression for the Hubble parameter and test it with observational data. Our findings not only support the validity of our proposed model, but also provide some insights into the coincidence problem and the Hubble tension in cosmology.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
Celia Escamilla-Rivera, Antonio Najera
Summary: The study shows that certain dark energy parametrization models are ruled out and a strong preference against the Chevallier-Polarski-Linder model. A mock GW catalogue suggests that approximately 1000 standard sirens are needed to constrain H-0 within a 1% relative error.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Celia Escamilla-Rivera, Maryi Carvajal, Cristian Zamora, Martin Hendry
Summary: This study proposes a new method to calibrate gamma-ray bursts (GRBs) as cosmological distance indicators using a machine learning architecture with data from Type Ia Supernovae (SNeIa) observations. By combining a Recurrent Neural Network (RNN) and a Bayesian Neural Network (BNN), the network's efficacy is extended by computing covariance matrices. This method can be used to implement a cosmographic reconstruction of the distance-redshift relation in different redshift regimes.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
Rodrigo Sandoval-Orozco, Celia Escamilla-Rivera
Summary: This paper discusses new solutions obtained through special analytical functions for solving the Friedmann equations, and constrains them with an updated compilation of observational Hubble data to address the issue of local H-0 tension.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Review
Physics, Multidisciplinary
Sebastian Bahamonde, Konstantinos F. Dialektopoulos, Celia Escamilla-Rivera, Gabriel Farrugia, Viktor Gakis, Martin Hendry, Manuel Hohmann, Jackson Levi Said, Jurgen Mifsud, Eleonora Di Valentino
Summary: In this Review, the development of teleparallel gravity as a gauge theory of translations is comprehensively introduced. The construction of consistent teleparallel theories that respect physical conditions such as local Lorentz invariance is described. Various modified teleparallel theories of gravity are discussed and connected into general classes of covariant gravitational theories. The cosmological consequences and observational implications of teleparallel gravity are also explored, along with the application of machine learning to gravity research.
REPORTS ON PROGRESS IN PHYSICS
(2023)
Article
Physics, Multidisciplinary
Julio C. Fabris, Oliver F. Piattella, Davi C. Rodrigues
Summary: Rastall introduced a stress-energy tensor which changes the form of the field equations of General Relativity while preserving the number of degrees of freedom. The Rastall field equations can be interpreted as GR with a redefined SET or imply different physical consequences in the matter sector. The study investigates the direct derivation of the Rastall field equations from two f (R)-gravity extensions, revealing similarities between these theories but limitations in fully recovering the Rastall SET.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Erendira Gutierrez-Luna, Belen Carvente, Victor Jaramillo, Juan Barranco, Celia Escamilla-Rivera, Catalina Espinoza, Myriam Mondragon, Dario Nunez
Summary: This study explores the possibility of incorporating particle physics motivated scalar fields into the dark matter cosmological model. The analysis is performed using one to two scalar fields to examine their impact on the cosmic flow. The results show that the combination of scalar fields has a significant effect on the cosmological expansion.
Article
Astronomy & Astrophysics
Maxence Corman, Abhirup Ghosh, Celia Escamilla-Rivera, Martin A. Hendry, Sylvain Marsat, Nicola Tamanini
Summary: The study explores the propagation of gravitational waves at cosmological distances, offering a new way to test modified theories of gravity at large scales. By considering a cosmological model with extra spatial dimensions, the paper derives the relation between the luminosity distance measured by GW detectors and the one inferred by EM observations. This relation is then used to constrain the number of cosmological extra dimensions and provide forecasts for future observations of massive black hole binary mergers.
Article
Astronomy & Astrophysics
Geovanny A. Rave-Franco, Celia Escamilla-Rivera, Jackson Levi Said
Summary: The study explores teleparallel gravity from a dynamical systems perspective, introducing a nonconstant degree of freedom to improve existing autonomous system models for a new dynamical analysis. By studying hyperbolic critical points, a possible solution to the H-0 tension in a cosmologically viable f(T,B) mixed power law model is suggested.