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
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
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
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
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
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
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
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
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
Astronomy & Astrophysics
Rajeev Kumar Jain, P. Jishnu Sai, Martin S. Sloth
Summary: This study calculates the primordial correlation between gravitons and a non-minimally coupled abelian gauge field in the early universe, and finds that this correlation satisfies new consistency relations in the three-point cross-correlation functions. The study shows that the interaction between gravitons and gauge fields may have implications for cosmological observables today.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Quantum Science & Technology
Lydia A. Kanari-Naish, Jack Clarke, Sofia Qvarfort, Michael R. Vanner
Summary: Cavity quantum optomechanics is a new platform for quantum science and technology that has various applications. This work introduces a pulsed approach to generate and verify non-Gaussian states of motion using the nonlinearity of the radiation-pressure interaction and photon-counting measurements. The authors also propose a protocol to measure the quadrature moments of the two mechanical oscillators using pulsed interactions, allowing for experimental characterization of bipartite mechanical quantum states. This scheme provides a new avenue for quantum experiments with entangled mechanical oscillators and has significant potential for quantum-information and sensing applications, as well as studying the quantum-to-classical transition.
QUANTUM SCIENCE AND TECHNOLOGY
(2022)
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
Shu-Lin Cheng, Da-Shin Lee, Kin-Wang Ng
Summary: We develop a nonperturbative method to examine the quantum fluctuation effects on the single-field inflationary models in a spatially flat FRW cosmological space-time using the Hartree factorization. We derive the modified Mukhanov-Sasaki equations for the mode functions of the quantum scalar field by introducing the nonzero Delta(B) term. We find that the presence of ultra slow roll inflation triggers the growth of Delta(B) and boosts the curvature perturbations, but the cosmic friction term may inhibit this boost effect.
Article
Astronomy & Astrophysics
Guilherme Brando, Kazuya Koyama, David Wands, Miguel Zumalacarregui, Ignacy Sawicki, Emilio Bellini
Summary: The study combines N-body gauge with Horndeski gravity theories to investigate the relativistic effects of scalar fields on the matter power spectrum at intermediate and large scales. It shows that the kineticity function at these scales enhances the amplitude of contributions from the extra degree of freedom, and identifies the purely relativistic origin of gravity acoustic oscillations in the matter power spectrum at large scales. This research provides insights into how certain modified gravity models can enhance gravity acoustic oscillations to detectable levels, offering a new test of gravity at scales probed by future galaxy and intensity-mapping surveys.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Obinna Umeh, Kazuya Koyama, Robert Crittenden
Summary: The study explores how the equivalence principle for non-standard matter fields on cosmological scales can be tested using galaxy cross-power spectrum and bispectrum, proposing a method to examine the equivalence principle through galaxy relative velocities.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Bartolomeo Fiorini, Kazuya Koyama, Albert Izard, Hans A. Winther, Bill S. Wright, Baojiu Li
Summary: We investigate the production of galaxy mock catalogues using COLA simulations in Modified Gravity (MG) models with the Halo Occupation Distribution (HOD) formalism. Our study shows that COLA accurately reproduces the matter power spectrum at the Dark Matter (DM) level, but is less accurate in reproducing the velocity field. By utilizing a simple Friends-of-Friends (FoF) finder and an empirical mass conversion method, we are able to produce halo catalogues in COLA that closely match those in N-body simulations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
A. Emir Gumrukcuoglu, Rampei Kimura, Michael Kenna-Allison, Kazuya Koyama
Summary: In Generalised Massive gravity, a non-linear analysis of perturbations around cosmological solutions was conducted, leading to the discovery of a new type of non-linear solution for the scalar mode and confirmation of the presence of the Vainshtein screening mechanism. The PPN parameter approaches its GR value at solar system scales and meets current constraints.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Jamie Donald-McCann, Florian Beutler, Kazuya Koyama, Minas Karamanis
Summary: MATRYOSHKA is a suite of neural-network-based emulators and accompanying python package that can provide fast and accurate predictions of the non-linear galaxy power spectrum. By combining linear component emulators with a non-linear boost component emulator, it is possible to predict the real space non-linear galaxy power spectrum with high accuracy.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jinglan Zheng, Gong-Bo Zhao, Yuting Wang, Xiaoyong Mu, Ruiyang Zhao, Weibing Zhang, Shuo Yuan, David Bacon, Kazuya Koyama
Summary: A new consistency test is proposed to validate the ?CDM cosmology using baryonic acoustic oscillations (BAO) and redshift space distortion (RSD) measurements. The test compares the predicted peak position of f sigma (8)(z) based on BAO observables with the peak position offered by RSD measurements. The test is demonstrated using simulated data from the DESI galaxy survey and is argued to complement existing methods and be less susceptible to systematics in RSD analysis.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Guilherme Brando, Bartolomeo Fiorini, Kazuya Koyama, Hans A. Winther
Summary: In this study, we compare and validate COLA simulations against existing emulators in the literature, and find that COLA method shows excellent agreement with the emulators under certain conditions. Furthermore, the implementation of massive neutrinos in COLA simulations and the ability to handle effective field theory of dark energy and modified gravity models are validated through experiments.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Joseph H. P. Jackson, Hooshyar Assadullahi, Kazuya Koyama, Vincent Vernin, David Wands
Summary: This article demonstrates the usage of importance sampling for reconstructing the statistics of rare cosmological fluctuations in stochastic inflation. The authors developed a publicly available package, PYFPT, that addresses the first-passage time problem of generic one-dimensional Langevin processes and its relation to curvature perturbation. The proposed method is applied to quadratic inflation and benchmarked against semi-analytical results, showing excellent agreement within the estimated statistical error. The computation time is relatively fast and can achieve low probability values compared to the observable universe. The study also investigates the impact of large-field boundaries on the tail of the probability distribution and demonstrates that non-perturbative deviations from Gaussianity are not always of the simple exponential type.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Emir Gumrukcuoglu, Kazuya Koyama
Summary: We argue that cubic order interactions between scalar and tensor gravitons play crucial roles in the decay of gravitational waves and the gradient instabilities of scalar perturbations. However, the existence of an infinite number of higher order interactions in generic Λ³ models makes it difficult to predict the fate of these instabilities.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Levon Pogosian, Marco Raveri, Kazuya Koyama, Matteo Martinelli, Alessandra Silvestri, Gong-Bo Zhao, Jian Li, Simone Peirone, Alex Zucca
Summary: This study explores modifications of the standard cold dark matter cosmological model and identifies the necessary features for alternative theories to alleviate tensions between cosmological datasets. The results provide important constraints on modified gravity models and suggest that late-time dynamical dark energy and modifications of gravity may not offer a solution to certain tensions.
Article
Astronomy & Astrophysics
Bartolomeo Fiorini, Kazuya Koyama, Albert Izard
Summary: This study investigates the effects of two Modified Gravity (MG) theories on large-scale structure and validates the accuracy of fast approximate COLA simulations in predicting these effects. The results show that using the first three even multipoles of the redshift space power spectrum is sufficient to reproduce the influence of MG theories on the real space power spectrum. Additionally, the study highlights the importance of considering non-linear contributions and suggests that the effects of MG theories on the bispectrum and voids can be dominated by non-linear galaxy bias.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Multidisciplinary
A. D. Gow, H. Assadullahi, J. H. P. Jackson, K. Koyama, V. Vennin, D. Wands
Summary: We propose a non-perturbative method to calculate the abundance of primordial black holes based on an arbitrary one-point probability distribution function for the primordial curvature perturbation, P(zeta). This method is essential for considering non-Gaussianities that cannot be treated using conventional perturbative expansions. By relating zeta to a Gaussian field through equating cumulative distribution functions, we can determine the full statistics of the density field. We demonstrate that the intermediate regime, rather than the far tail, is responsible for the enhanced formation of primordial black holes, and show that non-Gaussianity significantly affects the shape of the primordial black hole mass distribution.
Article
Astronomy & Astrophysics
Guilherme Brando, Kazuya Koyama, Hans A. Winther
Summary: We revisit and extend a method proposed by R. Scoccimarro to incorporate the Vainshtein screening mechanism in N-body simulations, allowing for the study of Horndeski theories that evade the speed limit on gravitational waves. The method computes a scale-dependent gravitational coupling that accounts for the screening of the fifth-force, significantly reducing computational time and complexity compared to solving the full equation of motion. By implementing this method in a COmoving Lagrangian Approximation (COLA) code and comparing it with full N-body simulations, we validate its accuracy and find high agreement for the prediction of the boost function, a crucial quantity for beyond-ACDM models.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Marco Raveri, Levon Pogosian, Matteo Martinelli, Kazuya Koyama, Alessandra Silvestri, Gong -Bo Zhao
Summary: In this paper, a non-parametric reconstruction method is presented to determine three time-dependent functions in the cosmological model. The data constraints on the structure of these functions and their eigenmodes are analyzed. The results show that the combination of all data can constrain 15 combined eigenmodes of the three functions and explain the tensions between datasets.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Review
Physics, Particles & Fields
Pierre Auclair, David Bacon, Tessa Baker, Tiago Barreiro, Nicola Bartolo, Enis Belgacem, Nicola Bellomo, Ido Ben-Dayan, Daniele Bertacca, Marc Besancon, Jose J. Blanco-Pillado, Diego Blas, Guillaume Boileau, Gianluca Calcagni, Robert Caldwell, Chiara Caprini, Carmelita Carbone, Chia-Feng Chang, Hsin-Yu Chen, Nelson Christensen, Sebastien Clesse, Denis Comelli, Giuseppe Congedo, Carlo Contaldi, Marco Crisostomi, Djuna Croon, Yanou Cui, Giulia Cusin, Daniel Cutting, Charles Dalang, Valerio De Luca, Walter Del Pozzo, Vincent Desjacques, Emanuela Dimastrogiovanni, Glauber C. Dorsch, Jose Maria Ezquiaga, Matteo Fasiello, Daniel G. Figueroa, Raphael Flauger, Gabriele Franciolini, Noemi Frusciante, Jacopo Fumagalli, Juan Garcia-Bellido, Oliver Gould, Daniel Holz, Laura Iacconi, Rajeev Kumar Jain, Alexander C. Jenkins, Ryusuke Jinno, Cristian Joana, Nikolaos Karnesis, Thomas Konstandin, Kazuya Koyama, Jonathan Kozaczuk, Sachiko Kuroyanagi, Danny Laghi, Marek Lewicki, Lucas Lombriser, Eric Madge, Michele Maggiore, Ameek Malhotra, Michele Mancarella, Vuk Mandic, Alberto Mangiagli, Sabino Matarrese, Anupam Mazumdar, Suvodip Mukherjee, Ilia Musco, Germano Nardini, Jose Miguel No, Theodoros Papanikolaou, Marco Peloso, Mauro Pieroni, Luigi Pilo, Alvise Raccanelli, Sebastien Renaux-Petel, Arianna I. Renzini, Angelo Ricciardone, Antonio Riotto, Joseph D. Romano, Rocco Rollo, Alberto Roper Pol, Ester Ruiz Morales, Mairi Sakellariadou, Ippocratis D. Saltas, Marco Scalisi, Kai Schmitz, Pedro Schwaller, Olga Sergijenko, Geraldine Servant, Peera Simakachorn, Lorenzo Sorbo, Lara Sousa, Lorenzo Speri, Daniele A. Steer, Nicola Tamanini, Gianmassimo Tasinato, Jesus Torrado, Caner Unal, Vincent Vennin, Daniele Vernieri, Filippo Vernizzi, Marta Volonteri, Jeremy M. Wachter, David Wands, Lukas T. Witkowski, Miguel Zumalacarregui, James Annis, Feanor Reuben Ares, Pedro P. Avelino, Anastasios Avgoustidis, Enrico Barausse, Alexander Bonilla, Camille Bonvin, Pasquale Bosso, Matteo Calabrese, Mesut Caliskan, Jose A. R. Cembranos, Mikael Chala, David Chernoff, Katy Clough, Alexander Criswell, Saurya Das, Antonio da Silva, Pratika Dayal, Valerie Domcke, Ruth Durrer, Richard Easther, Stephanie Escoffier, Sandrine Ferrans, Chris Fryer, Jonathan Gair, Chris Gordon, Martin Hendry, Mark Hindmarsh, Deanna C. Hooper, Eric Kajfasz, Joachim Kopp, Savvas M. Koushiappas, Utkarsh Kumar, Martin Kunz, Macarena Lagos, Marc Lilley, Joanes Lizarraga, Francisco S. N. Lobo, Azadeh Maleknejad, C. J. A. P. Martins, P. Daniel Meerburg, Renate Meyer, Jose Pedro Mimoso, Savvas Nesseris, Nelson Nunes, Vasilis Oikonomou, Giorgio Orlando, Ogan Ozsoy, Fabio Pacucci, Antonella Palmese, Antoine Petiteau, Lucas Pinol, Simon Portegies Zwart, Geraint Pratten, Tomislav Prokopec, John Quenby, Saeed Rastgoo, Diederik Roest, Kari Rummukainen, Carlo Schimd, Aurelia Secroun, Alberto Sesana, Carlos F. Sopuerta, Ismael Tereno, Andrew Tolley, Jon Urrestilla, Elias C. Vagenas, Jorinde van de Vis, Rien van de Weygaert, Barry Wardell, David J. Weir, Graham White, Bogumila Swiezewska, Valery I. Zhdanov
Summary: This publication provides an overview of the latest advancements in LISA cosmology, including theory and methods, and identifies new opportunities to probe the universe using gravitational-wave observations by LISA.
LIVING REVIEWS IN RELATIVITY
(2023)
