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Astronomy & Astrophysics
Luca Marchetti, Daniele Oriti
Summary: This research derives effective dynamics for scalar cosmological perturbations from quantum gravity in the framework of group field theory condensate cosmology. It establishes a connection between fundamental quantum gravity models and cosmological observations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Keisuke Inomata
Summary: This study focuses on scalar perturbations induced by non-linear interactions at second order in perturbations. Analytic solutions for induced scalar perturbations in a perfect fluid are derived, with specific consideration for perturbations in radiation-dominated and matter-dominated eras. The evolution of induced scalar perturbations from outside to inside the horizon is also discussed using the analytic solutions.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Markus B. Froeb, William C. C. Lima
Summary: We introduce a recent approach to construct gauge-invariant relational observables in gravity within the framework of cosmological perturbation theory. These observables are built using a field-dependent coordinate system, specifically geodesic lightcone coordinates. We demonstrate that these observables are gauge-independent in the fully nonlinear theory and take the expected form when the geodesic lightcone gauge for the metric is adopted. Explicit expressions for the Sasaki-Mukhanov variable at linear order and the Hubble rate, as measured by both geodesic and inflaton co-moving observers, to second order are provided. Furthermore, we show that the well-known linearized equations of motion for the Sasaki-Mukhanov variable and the scalar constraint variables are derived from the gauge-invariant Einstein's equations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Mio Kubota, Kin-ya Oda, Keigo Shimada, Masahide Yamaguchi
Summary: This study investigates cosmological perturbations ofscalar-tensor theories in Palatini formalism. By introducing actions and computing perturbations in different frames, it is shown that the sound speed of gravitational waves is unity for certain models. Additionally, the presence of ghosts and potential deviations in sound speed in Palatini formalism are explored, with the conclusion that ghost-free terms can still serve as dark energy and inflaton.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Luis E. Padilla, Juan Carlos Hidalgo, Dario Nunez
Summary: This study investigates the evolution of nonlinear superhorizon perturbations in a universe dominated by a complex scalar field using the gradient expansion approach on a constant mean curvature slicing. General solutions valid to second order in the ratio H-1/L are derived for scalar field inhomogeneities of size L subject to an arbitrary canonical potential, with explicit solutions calculated for the quadratic and quartic potentials, highlighting their relevance in setting initial conditions for simulations of primordial black hole formation.
Article
Astronomy & Astrophysics
Srijita Sinha, Narayan Banerjee
Summary: In this study, perturbations in a scalar field model driving recent acceleration were investigated, revealing distinctive qualitative features compared to the traditional ΛCDM model, particularly in reducing the amplitude of the matter power spectrum at an 8h(-1) Mpc scale.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
Jen-Tsung Hsiang, Bei-Lok Hu
Summary: This paper discusses the entropy of cosmological perturbations and some important properties of quantum fields, presenting different methods for addressing this issue and deriving conclusions through calculations and analysis.
Article
Astronomy & Astrophysics
Jinn-Ouk Gong, Maria Mylova
Summary: In this study, we examine the validity of the classical approximation of the waterfall phase transition in hybrid inflation from an effective field theory perspective. By integrating out the fluctuations of the waterfall field up to one-loop order, an effective field theory is constructed. Assuming slow-roll conditions are satisfied, we find that the backreaction of the waterfall field fluctuations can significantly impact the evolution of the system, rendering the classical approximation invalid. We derive the necessary constraint to ensure the validity of the effective field theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
D. Racco, A. Riotto
Summary: The large-scale perturbations in dark matter generated by the freeze-in mechanism are shown to be only of adiabatic nature, which is not contradictory to the current stringent constraints on isocurvature perturbations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
M. Knabenhans, J. Stadel, D. Potter, J. Dakin, S. Hannestad, T. Tram, S. Marelli, A. Schneider, R. Teyssier, P. Fosalba, S. Andreon, N. Auricchio, C. Baccigalupi, A. Balaguera-Antolinez, M. Baldi, S. Bardelli, P. Battaglia, R. Bender, A. Biviano, C. Bodendorf, E. Bozzo, E. Branchini, M. Brescia, C. Burigana, R. Cabanac, S. Camera, V Capobianco, A. Cappi, C. Carbone, J. Carretero, C. S. Carvalho, R. Casas, S. Casas, M. Castellano, G. Castignani, S. Cavuoti, R. Cledassou, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, L. Corcione, J. Coupon, H. M. Courtois, A. Da Silva, S. de la Torre, D. Di Ferdinando, C. A. J. Duncan, X. Dupac, G. Fabbian, S. Farrens, P. G. Ferreira, F. Finelli, M. Frailis, E. Franceschi, S. Galeotta, B. Garilli, C. Giocoli, G. Gozaliasl, J. Gracia-Carpio, F. Grupp, L. Guzzo, W. Holmes, F. Hormuth, H. Israel, K. Jahnke, E. Keihanen, S. Kermiche, C. C. Kirkpatrick, B. Kubik, M. Kunz, H. Kurki-Suonio, S. Ligori, P. B. Lilje, I Lloro, D. Maino, O. Marggraf, K. Markovic, N. Martinet, F. Marulli, R. Massey, N. Mauri, S. Maurogordato, E. Medinaceli, M. Meneghetti, B. Metcalf, G. Meylan, M. Moresco, B. Morin, L. Moscardini, E. Munari, C. Neissner, S. M. Niemi, C. Padilla, S. Paltani, F. Pasian, L. Patrizii, V Pettorino, S. Pires, G. Polenta, M. Poncet, F. Raison, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, R. Saglia, A. G. Sanchez, D. Sapone, P. Schneider, V Scottez, A. Secroun, S. Serrano, C. Sirignano, G. Sirri, L. Stanco, F. Sureau, P. Tallada Crespi, A. N. Taylor, M. Tenti, I Tereno, R. Toledo-Moreo, F. Torradeflot, L. Valenziano, J. Valiviita, T. Vassallo, M. Viel, Y. Wang, N. Welikala, L. Whittaker, A. Zacchei, E. Zucca
Summary: EuclidEmulator2 is a fast and accurate predictor for the nonlinear correction of the matter power spectrum, achieving 2% accuracy in an eight-dimensional parameter space. By improving the quality of N-body simulations and conducting high fidelity tests, it has been successfully applied in various comparisons and blind tests, showing superior accuracy of nonlinear correction factors at z <= 3 compared to high-resolution dark-matter-only simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Keisuke Inomata, Evan McDonough, Wayne Hu
Summary: Future experiments on cosmic microwave background, gravitational wave, and large scale structure will allow us to study the primordial power spectrum on small scales, potentially revealing the mechanisms and correlations behind the formation of primordial black holes.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Francisco X. Linares Cedeno, Ulises Nucamendi
Summary: In this study, we focus on the cosmological evolution of linear perturbations of matter and geometry within the framework of Unimodular Gravity. We calculate the equivalent expressions to the commonly used Newtonian and Synchronous gauges. Our analysis shows that Unimodular Gravity requires maintaining anisotropic stress in the Newtonian gauge and does not allow for setting the cold dark matter comoving frame in the Synchronous gauge.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Yuejia Zhai, William Giare, Carsten van de Bruck, Eleonora Di Valentino, Olga Mena, Rafael C. Nunes
Summary: We analyze a cosmological model with interaction between dark energy and dark matter using data from three independent experiments: Planck, Atacama Cosmology Telescope, and WMAP. Regardless of the combination of datasets, the results consistently support an interacting dark sector with a 95% confidence level. This preference remains consistent when cross-checked with independent probes and yields a value for the expansion rate H0 consistent with local distance ladder measurements.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Katsuki Aoki, Mohammad Ali Gorji, Shuntaro Mizuno, Shinji Mukohyama
Summary: The study focuses on slow-roll single field inflation in the context of consistent D -> 4 Einstein-Gauss-Bonnet gravity. Apart from the standard attractor regime, a new attractor regime known as the Gauss-Bonnet attractor is identified, providing insights into power spectra, spectral tilts, and consistency relations. The Gauss-Bonnet term introduces a nonlinear contribution to the gravitational waves dispersion relation, offering a new scenario for primordial gravitational waves that can be tested through observations. Furthermore, the analysis delves into the non-Gaussianity of gravitational waves and estimates nonlinear parameters for different helicities.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Subhajit Ghosh, Soubhik Kumar, Yuhsin Tsaia
Summary: Dark radiation is a potential candidate beyond the Standard Model, and its perturbations can have isocurvature components under certain conditions. This study derives constraints on uncorrelated and correlated dark radiation density isocurvature perturbations and explores the differences between free-streaming dark radiation and coupled dark radiation. The preference for a blue-tilt dark radiation isocurvature spectrum is found, which affects the estimation of the Hubble constant and relaxes the H-0 tension.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Ning Bao, ChunJun Cao, Sean M. Carroll, Aidan Chatwin-Davies, Nicholas Hunter-Jones, Jason Pollack, Grant N. Remmen
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Physics, Multidisciplinary
Kimberly K. Boddy, Sean M. Carroll, Jason Pollack
FOUNDATIONS OF PHYSICS
(2016)
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Astronomy & Astrophysics
Ning Bao, Sean M. Carroll, Ashmeet Singh
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2017)
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Astronomy & Astrophysics
Anthony Aguirre, Sean M. Carroll, Matthew C. Johnson
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2012)
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Multidisciplinary Sciences
Brian Kloppenborg, Robert Stencel, John D. Monnier, Gail Schaefer, Ming Zhao, Fabien Baron, Hal McAlister, Theo ten Brummelaar, Xiao Che, Chris Farrington, Ettore Pedretti, P. J. Sallave-Goldfinger, Judit Sturmann, Laszlo Sturmann, Nathalie Thureau, Nils Turner, Sean M. Carroll
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Astronomy & Astrophysics
Sean M. Carroll, Heywood Tam, Ingunn Kathrine Wehus
Correction
Astronomy & Astrophysics
Lotty Ackerman, Sean M. Carroll, Mark B. Wise
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Astronomy & Astrophysics
Lotty Ackerman, Matthew R. Buckley, Sean M. Carroll, Marc Kamionkowski
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Sean M. Carroll, Sonny Mantry, Michael J. Ramsey-Musolf
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Sean M. Carroll, Chien-Yao Tseng, Mark B. Wise
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Astronomy & Astrophysics
Kimberly K. Boddy, Sean M. Carroll, Mark Trodden
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Astronomy & Astrophysics
Grant N. Remmen, Sean M. Carroll
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Astronomy & Astrophysics
Grant N. Remmen, Sean M. Carroll
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Physics, Multidisciplinary
Sean M. Carroll, Sonny Mantry, Michael J. Ramsey-Musolf, Christoper W. Stubbs
PHYSICAL REVIEW LETTERS
(2009)