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Related papers: Constraints on running vacuum model with $H(z)$ an…

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We study a special running vacuum model (RVM) with $\Lambda = 3 \alpha H^2+3\beta H_0^4 H^{-2}+\Lambda_0$, where $\alpha$, $\beta$ and $\Lambda_0$ are the model parameters and $H$ is the Hubble one. This RVM has non-analytic background…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-31 Chao-Qiang Geng , Chung-Chi Lee , Lu Yin

We investigate the power spectra of the CMB temperature and matter density in the running vacuum model (RVM) with the time-dependent cosmological constant of $\Lambda = 3 \nu H^2 + \Lambda_0$, where $H$ is the Hubble parameter. In this…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-08 Jin-Jun Zhang , Chung-Chi Lee , Chao-Qiang Geng

We investigate the running cosmological constant model with dark energy linearly proportional to the Hubble parameter, $\Lambda = \sigma H + \Lambda_0$, in which the $\Lambda$CDM limit is recovered by taking $\sigma=0$. We derive the linear…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-22 Chao-Qiang Geng , Chung-Chi Lee , Kaituo Zhang

We investigate observational constraints on the running vacuum model (RVM) of $\Lambda=3\nu (H^{2}+K/a^2)+c_0$ in the spatially curved universe, where $\nu$ is the model parameter, $K$ corresponds to the spatial curvature constant, and…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-29 Chao-Qiang Geng , Yan-Ting Hsu , Lu Yin , Kaituo Zhang

In cosmology, phenomenologically motivated expressions for running vacuum are commonly parametrized as linear functions $\Lambda(H^2)$ or $\Lambda(R)$. Such kind of models assume an equation of state for vacuum given by $\,\overline…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-30 E. L. D. Perico , D. A. Tamayo

A substantial body of phenomenological and theoretical work over the last few years strengthens the possibility that the vacuum energy density (VED) of the universe is dynamical, and in particular that it adopts the `running vacuum model'…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Joan Sola Peracaula , Adria Gomez-Valent , Javier de Cruz Perez , Cristian Moreno-Pulido

In this study, we consider three dark energy models in which $\Lambda$ is not constant, but has a dynamic nature that depends on the Hubble parameter $H$ and/or its time derivative $\dot{H}$. We analyze the generalized running vacuum model,…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Christine R. Farrugia , Joseph Sultana , Jurgen Mifsud

It is well-known that a constant $\Lambda$-term is a traditional building block of the concordance $\Lambda$CDM model. We show that this assumption is not necessarily the optimal one from the phenomenological point of view. The class of…

General Relativity and Quantum Cosmology · Physics 2016-05-23 Adrià Gómez-Valent , Joan Solà , Javier de Cruz Pérez

We use updated Hubble parameter and baryon acoustic oscillation data, as well as other lower-redshift Type Ia supernova, Mg II reverberation-measured quasar, quasar angular size, H II starburst galaxy, and Amati-correlated gamma-ray burst…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-31 Shulei Cao , Bharat Ratra

The cosmological term, $\Lambda$, was introduced $104$ years ago by Einstein in his gravitational field equations. Whether $\Lambda$ is a rigid quantity or a dynamical variable in cosmology has been a matter of debate for many years,…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-20 Joan Sola , Adria Gomez-Valent , Javier de Cruz Perez , Cristian Moreno-Pulido

We use all available baryon acoustic oscillation distance measurements and Hubble parameter data to constrain the cosmological constant $\Lambda$, dynamical dark energy, and spatial curvature in simple cosmological models. We find that the…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-19 Joseph Ryan , Sanket Doshi , Bharat Ratra

For different gravitational models we consider limitations on their parameters coming from recent observational data for type Ia supernovae, baryon acoustic oscillations, and from 34 data points for the Hubble parameter $H(z)$ depending on…

General Relativity and Quantum Cosmology · Physics 2014-11-06 G. S. Sharov , E. G. Vorontsova

We examine the decay vacuum model with a parameter $\epsilon$ that indicates the vacuum energy decay rate. By constraining this model with cosmic microwave background radiation, baryon acoustic oscillation, type Ia supernovae and 30 H(z)…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-04 Yang-Jie Yan , Deng Wang , Xin-He Meng

In this work, we present comprehensive observational constraints on the time-varying vacuum $\Lambda(t)$CDM cosmology using the latest baryon acoustic oscillation (BAO) data from Dark Energy Spectroscopic Instrument (DESI) Data Release 2…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-05 Olga Avsajanishvili

Despite the outstanding achievements of modern cosmology, the classical dispute on the precise value of $H_0$, which is the first ever parameter of modern cosmology and one of the prime parameters in the field, still goes on and on after…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-22 Joan Sola , Adria Gomez-Valent , Javier de Cruz Perez

Presently, we are facing a 3$\sigma$ tension in the most basic cosmological parameter -- the Hubble constant $H_0$. This tension arises when fitting the Lambda-cold-dark-matter model ($\Lambda$CDM) to the high-precision…

General Physics · Physics 2017-10-18 Steffen Hahn , Ralf Hofmann

We discuss the cosmological degeneracy between the Hubble parameter H(z), the age of the universe and cosmological parameters describing simple variations from the minimal LCDM model. We show that independent determinations of the Hubble…

Astrophysics · Physics 2014-11-18 Daniel G. Figueroa , Licia Verde , Raul Jimenez

In this paper we compare data to theory. We use a compilation of the most recent cosmic microwave background (CMB) measurements to constrain Hubble's constant h, the baryon fraction Omega_b, and the cosmological constant lambda. We fit h-,…

Astrophysics · Physics 2008-02-03 Charles H. Lineweaver , Domingos Barbosa , Alain Blanchard , James G. Bartlett

We derive for the first time the growth index of matter perturbations of the FLRW flat cosmological models in which the vacuum energy depends on redshift. A particularly well motivated model of this type is the so-called quantum field…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-09 Spyros Basilakos , Joan Solà

We use 28 Hubble parameter, $H(z)$, measurements at intermediate redshifts $0.07 \leq z \leq 2.3$ to determine the present-day Hubble constant $H_0$ in four cosmological models. We measure $H_0 = 68.3^{ +2.7}_{ -2.6 }, 68.4^{ +2.9 }_{ -3.3…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-26 Yun Chen , Suresh Kumar , Bharat Ratra
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