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Linear perturbations of Friedmann-Robertson-Walker universes with any curvature and cosmological constant are studied in a general gauge without decomposition into harmonics. Desirable gauges are selected as those which embody best Mach's…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jiri Bicak , Joseph Katz , Donald Lynden-Bell

In this paper the implications of a recently proposed phenomenological model of cosmology, the Asymptotic Cosmological Model (ACM), on the behavior of scalar perturbations are studied. Firstly we discuss new fits of the ACM at the…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-05 J. L. Cortes , J. Indurain

Effective field theory provides a perturbative framework to study the evolution of cosmological large-scale structure. We investigate the underpinnings of this approach, and suggest new ways to compute correlation functions of cosmological…

High Energy Physics - Theory · Physics 2014-07-16 Sean M. Carroll , Stefan Leichenauer , Jason Pollack

A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the coincidence and magnitude fine-tuning problems of the Cosmological Constant…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-14 Brett Bochner

The time evolution of primordial fluctuations conceals a wealth of insights into the high-energy physics at play during the earliest moments of our Universe, which is ultimately encoded in late-time spatial correlation functions. However,…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-12 Lucas Pinol , Sébastien Renaux-Petel , Denis Werth

The higher order generalisation of the clockwork mechanism to gravitational interactions provides a means to generate an exponentially suppressed coupling to matter from a fundamental theory of multiple interacting gravitons, without…

High Energy Physics - Theory · Physics 2023-08-09 Kieran Wood , Paul M. Saffin , Anastasios Avgoustidis

Primordial perturbations in our universe are believed to have a quantum origin, and can be described by the wavefunction of the universe (or equivalently, cosmological correlators). It follows that these observables must carry the imprint…

High Energy Physics - Theory · Physics 2021-06-16 Scott Melville , Enrico Pajer

Cosmography is a useful tool to constrain cosmological models, in particular dark energy models. In the case of modified theories of gravity, where the equations of motion are generally quite complicated, cosmography can contribute to…

General Relativity and Quantum Cosmology · Physics 2010-12-23 Mariam Bouhmadi-Lopez , Salvatore Capozziello , Vincenzo F. Cardone

A phenomenological formalism is presented in which the apparent acceleration of the universe is generated by large-scale structure formation, thus eliminating the magnitude and coincidence fine-tuning problems of the Cosmological Constant…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-14 Brett Bochner

Inspired by recent advances in observational astrophysics and continued explorations in the field of analog gravity, we discuss the prospect of simulating models of cosmology within the context of synthetic mechanical lattice experiments.…

Mesoscale and Nanoscale Physics · Physics 2025-04-22 Brendan Rhyno , Ivan Velkovsky , Peter Adshead , Bryce Gadway , Smitha Vishveshwara

We propose a new method for obtaining an effective Friedmann-Lema\^itre-Robertson-Walker (FLRW) cosmology from the quantum gravity dynamics of group field theory (GFT), based on the idea that an FLRW universe is characterised by a few…

General Relativity and Quantum Cosmology · Physics 2022-03-10 Steffen Gielen , Luca Marchetti , Daniele Oriti , Axel Polaczek

We obtain the general cosmological evolution equations for a classically consistent theory of bimetric gravity. Their analytic solutions are demonstrated to generically allow for a cosmic evolution starting out from a matter dominated FLRW…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Mikael von Strauss , Angnis Schmidt-May , Jonas Enander , Edvard Mortsell , S. F. Hassan

We introduce COBRA (Cosmology with Optimally factorized Bases of Radial Approximants), a novel framework for rapid computation of large-scale structure observables. COBRA separates scale dependence from cosmological parameters in the linear…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-15 Thomas Bakx , Nora Elisa Chisari , Zvonimir Vlah

The interpretation of cosmological observations relies on a notion of an average Universe, which is usually considered as the homogeneous and isotropic Friedmann-Lema\^itre-Robertson-Walker (FLRW) model. However, inhomogeneities may…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-24 Michel-Andrès Breton , Pierre Fleury

We implement the worldline formalism in phase space to compute scattering amplitudes. First, the Feynman rules exhibit several useful universal features, reflecting elements of the symplectic geometry of the phase space target. Next,…

High Energy Physics - Theory · Physics 2025-09-09 Joon-Hwi Kim

We show that the wavefunction of the universe in theories of conformally coupled scalars in power-law Friedmann-Robertson-Walker (FRW) cosmologies satisfies a graphical coaction, by means of which we can understand its complete analytic…

High Energy Physics - Theory · Physics 2026-03-27 Andrew McLeod , Andrzej Pokraka , Lecheng Ren

We investigate the properties of the (complex) coefficients obtained in a spherical harmonic representation of temperature maps of the cosmic microwave background (CMB). We study the effect of the coefficient phase only, as well as the…

Astrophysics · Physics 2009-11-10 Andrew Stannard , Peter Coles

We present results for the cosmic non-linear density-fluctuation power spectrum based on the analytical formalism developed in [1] which allows us to study cosmic structure formation based on Newtonian particle dynamics in phase-space. This…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 Tristan Daus , Elena Kozlikin

We study the accuracy with which cosmological parameters can be determined from real space power spectrum of matter density contrast at weakly nonlinear scales using analytical approaches. From power spectra measured in $N$-body simulations…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-03 Ken Osato , Takahiro Nishimichi , Francis Bernardeau , Atsushi Taruya

Recent observational indications of an accelerating universe enhance the interest in studying models with a cosmological constant. We investigate cosmological expansion (FRW metric) with $\Lambda>0$ for a general linear equation of state…

General Relativity and Quantum Cosmology · Physics 2016-08-31 A. S. Silbergleit