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The time-dependence of correlation functions under the influence of classical equations of motion is described by an exact evolution equation. For conservative systems thermodynamic equilibrium is a fixed point of these equations. We show…

High Energy Physics - Theory · Physics 2009-10-30 Christof Wetterich

The ``in-in'' formalism is reviewed and extended, and applied to the calculation of higher-order Gaussian and non-Gaussian correlations in cosmology. Previous calculations of these correlations amounted to the evaluation of tree graphs in…

High Energy Physics - Theory · Physics 2008-11-26 Steven Weinberg

We show that dissipative effects have a significant impact on the evolution of cosmological scalar fields, leading to friction, entropy production and field fluctuations. We explicitly compute the dissipation coefficient for different…

High Energy Physics - Phenomenology · Physics 2015-05-06 Sam Bartrum , Arjun Berera , Joao G. Rosa

We study the coaction of cosmological wavefunction coefficients of conformally coupled scalars in FRW background of a two-site example, which turns out to have an elegant diagrammatic interpretation. We show how the coaction acts on the…

High Energy Physics - Theory · Physics 2026-03-27 Yuhan Fu , Jiahao Liu

We outline the key-steps toward the construction of a physical, fully relativistic cosmology. The influence of inhomogeneities on the effective evolution history of the Universe is encoded in backreaction terms and expressed through…

General Relativity and Quantum Cosmology · Physics 2012-07-06 Thomas Buchert

The origin of the large scale structure in the universe - galaxies, quasars, clusters, voids, sheets - is one of the most important questions in cosmology. One can show that some non-thermal energy density fluctuations must have been…

Astrophysics · Physics 2007-05-23 Mairi Sakellariadou

In this paper we present a cosmological model arising from a non-conservative gravitational theory proposed in [PRD 95, 101501(R) (2017)]. The novel feature where comparing with previous implementations of dissipative effects in gravity is…

General Relativity and Quantum Cosmology · Physics 2018-05-28 Júlio C. Fabris , Hermano Velten , Thiago R. P. Caramês , Matheus J. Lazo , Gastão S. F. Frederico

I investigate a class of dynamical systems in which finite pieces of spacetime contain finite amounts of information. Most of the guiding principles for designing these systems are drawn from general relativity: the systems are…

High Energy Physics - Theory · Physics 2007-05-23 David Hillman

A role of skew-symmetric differential forms in mathematical physics relates to the fact that they reflect the properties of conservation laws. The closed exterior forms correspond to the conservation laws for physical fields, whereas the…

Mathematical Physics · Physics 2007-05-23 L. I. Petrova

We introduce a dynamical model to reduce a large cosmological constant to a sufficiently small value. The basic ingredient in this model is a distinction which has been made between the two unit systems used in cosmology and particle…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Yousef Bisabr

All cosmological observations to date are consistent with adiabatic, Gaussian and nearly scale invariant initial conditions. These findings provide strong evidence for a particular symmetry breaking pattern in the very early universe (with…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-26 Jens Chluba , Jan Hamann , Subodh P. Patil

The universal symmetry, or conservation, of complexity underlies any law or principle of system dynamics and describes the unceasing transformation of dynamic information into dynamic entropy as the unique way to conserve their sum, the…

General Physics · Physics 2014-05-15 Andrei P. Kirilyuk

A mathematical model of the Universe evolution, based on asymmetric doublet of classical and phantom dcalar Higgs fields with a kinetic connection between the components, has been constructed and studied. A detailed qualitative analysis was…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Yu. G. Ignat'ev , I. A. Kokh

The galactic evolutionary theory is now sufficiently mature to provide information about the galaxy formation phase. From evolutionary models we establish a link between the present features of late type galaxies and the protogalactic…

Astrophysics · Physics 2011-04-15 Claudio Firmani , Xavier Hernández , Vladimir Avila-Reese

We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Genly Leon , Emmanuel N. Saridakis

It is shown that the dynamical evolution of linear perturbations on a static space-time is governed by a constrained wave equation for the extrinsic curvature tensor. The spatial part of the wave operator is manifestly elliptic and…

General Relativity and Quantum Cosmology · Physics 2009-10-31 O. Sarbach , M. Heusler , O. Brodbeck

The linear cosmological perturbation theory of an almost homogeneous and isotropic perfect fluid universe is reconsidered and formally simplified by introducing new covariant and gauge-invariant variables with physical interpretations on…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Winfried Zimdahl

Collapse models possibly suggest the need for a better understanding of the structure of space-time. We argue that physical space, and space-time, are emergent features of the Universe, which arise as a result of dynamical collapse of the…

Quantum Physics · Physics 2017-02-01 Tejinder P. Singh

We study the dynamics of the scalar modes of linear perturbations around a flat, homogeneous and isotropic background in loop quantum cosmology. The equations of motion include quantum geometry effects and hold at all curvature scales so…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Edward Wilson-Ewing

We investigate the evolution of linear perturbations in the Symmetric Teleparallel Gravity, namely $f(Q)$ gravity, for which we design the $f(Q)$ function to match specific expansion histories. We consider different evolutions of the…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-10 Inês S. Albuquerque , Noemi Frusciante