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Coherent states consist of superposition of infinite number of particles and do not have a classical analogue. We study their evolution in a FLRW cosmology and show that only when full quantum corrections are considered, they may survive…

High Energy Physics - Phenomenology · Physics 2015-08-26 Houri Ziaeepour

The Cosmological Principle (CP) -- the notion that the Universe is spatially isotropic and homogeneous on large scales -- underlies a century of progress in cosmology. It is conventionally formulated through the…

We investigate a cosmological scenario in which the dark matter particles can be created during the evolution of the Universe. By regarding the Universe as an open thermodynamic system and using non-equilibrium thermodynamics, we examine…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-20 Z. Safari , K. Rezazadeh , B. Malekolkalami

Modern cosmology is based on the cosmological principle, which states that the Universe is statistically homogeneous and isotropic. When applied in its strict -- rather than statistical -- sense, the cosmological principle leads to the…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-03 Pierre Fleury

A late epoch cosmic acceleration may be naturally entangled with cosmic coincidence -- the observation that at the onset of acceleration the vacuum energy density fraction nearly coincides with the matter density fraction. In this Letter we…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-07 Ciaran Doolin , Ishwaree P. Neupane

In universes with significant curvature or cosmological constant, cosmic microwave background (CMB) anisotropies are created very recently via the Rees-Sciama or integrated Sachs-Wolfe effects. This causes the CMB anisotropies to become…

Astrophysics · Physics 2009-10-30 S. P. Boughn , R. G. Crittenden , N. G. Turok

Cosmological inflation is a popular paradigm for understanding Cosmic Microwave Background Radiation (CMBR); however, it faces many conceptual challenges. An alternative mechanism to inflation for generating an almost scale-invariant…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-24 S. Mahesh Chandran , S. Shankaranarayanan

With the era of precision cosmology upon us, and upcoming surveys expected to further improve the precision of our observations below the percent level, ensuring the accuracy of our theoretical cosmological model is of the utmost…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-30 Hayley J. Macpherson

The standard cosmological model is in the midst of a stress test, thanks to the tension between supernovae-based measurements of the Hubble constant $H_{0}$ and inferences of its values from Cosmic Microwave Background (CMB) anisotropies.…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-05 K. Rezazadeh , A. Ashoorioon , D. Grin

We consider a generic cosmological model which allows for non-gravitational direct couplings between dark matter and dark energy. The distinguishing cosmological features of these couplings can be probed by current cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Carsten van de Bruck , Jurgen Mifsud

A discrete space-time structure lying at about the Planck scale may become manifest in the form of very small violations of the conservation of the matter energy-momentum tensor. In order to include such kind of violations, forbidden within…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-15 Susana J. Landau , Micol Benetti , Alejandro Perez , Daniel Sudarsky

Faced by recent evidence for a flat universe dominated by dark energy, cosmologists grapple with deep cosmic enigmas such as the cosmological constant problem, extreme fine-tuning and the cosmic coincidence problem. The extent to which we…

Astrophysics · Physics 2016-08-30 Greg Huey , Benjamin D. Wandelt

We construct the cosmological model to explain the cosmological constant problem. We built the extension of the standard cosmological model $\Lambda$CDM by consideration of decaying vacuum energy represented by the running cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-08 Marek Szydlowski

We constrain an interacting, holographic dark energy model, first proposed by two of us in [1], with observational data from supernovae, CMB shift, baryon acoustic oscillations, x-rays, and the Hubble rate. The growth function for this…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-21 Iván Durán , Diego Pavón , Winfried Zimdahl

Recently there have been claims on model-independent evidence of dynamical dark energy. Herein we consider a fairly general class of cosmological models with a time-evolving cosmological term of the form $\Lambda(H)=C_0+C_H H^2+C_{\dot{H}}…

General Relativity and Quantum Cosmology · Physics 2015-10-08 Joan Sola , Adria Gomez-Valent , Javier de Cruz Perez

The evolution of cosmological large-scale perturbations is described in terms of the concordant model based on the recent discovery of cosmic vacuum. It is demonstrated that the process is robustly controlled by a few epoch-independent…

Astrophysics · Physics 2016-08-30 Arthur D. Chernin

A new vision of the beginning and expansion of our universe has produced a solution to the vacuum energy problem (also known as "cosmological constant problem"). A new dynamic of cellular spaces and a discrete time has space being produced…

Astrophysics · Physics 2007-05-23 Charles B. Leffert

A range of cosmological observations demonstrate an accelerated expansion of the Universe, and the most likely explanation of this phenomenon is a cosmological constant. Given the importance of understanding the underlying physics, it is…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-07 Karoline Loeve , Kristine Simone Nielsen , Steen H. Hansen

We investigate the observational viability of a class of cosmological models in which the vacuum energy density decays linearly with the Hubble parameter, resulting in a production of cold dark matter particles at late times. Similarly to…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-01 C. Pigozzo , M. A. Dantas , S. Carneiro , J. S. Alcaniz

We investigate a relativistic cosmological model with background rotation, sourced by a non-perfect fluid with anisotropic stress. A modified version of the CLASS Boltzmann code is employed to perform Monte Carlo Markov Chain analyses…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-16 Micol Benetti , David A. Cook , Saulo Carneiro