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We show that atomic clock measurements provides an exceptionally sensitive Solar System probe of scalar tensor dark energy. By connecting variations in Newton's constant and differential clock drifts to the dynamics of a single dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-19 Oem Trivedi

We extend the scalar-tensor reconstruction techniques for classical cosmology frameworks, in the context of loop quantum cosmology. After presenting in some detail how the equations are generalized in the loop quantum cosmology case, we…

General Relativity and Quantum Cosmology · Physics 2016-08-24 V. K. Oikonomou

Strong lensing time delay cosmography has excellent complementarity with other dark energy probes, and will soon have abundant systems detected. We investigate two issues in the imaging and spectroscopic followup required to obtain the time…

Cosmology and Nongalactic Astrophysics · Physics 2015-04-16 Eric V. Linder

We use the statistics of strong gravitational lensing based on the Cosmic Lens All-Sky Survey (CLASS) data to constrain cosmological parameters in a spatially-flat, inverse power-law potential energy density, scalar-field dark energy…

Astrophysics · Physics 2009-11-10 Kyu-Hyun Chae , Gang Chen , Bharat Ratra , Dong-Wook Lee

We consider a varieties of quintessence scalar field models in a homogeneous and isotropic geometry of the universe with zero spatial curvature aiming to provide stringent constraints using a series of cosmological data sets, namely, the…

General Relativity and Quantum Cosmology · Physics 2019-07-24 Weiqiang Yang , M. Shahalam , Barun Pal , Supriya Pan , Anzhong Wang

The abundance of galaxy clusters in the low-redshift universe provides an important cosmological test, constraining a product of the initial amplitude of fluctuations and the amount by which they have grown since early times. The degeneracy…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-21 Yuba Amoura , Nicole E. Drakos , Anael Berrouet , James E. Taylor

The clustering of galaxy clusters is a powerful cosmological tool, which can help to break degeneracies between parameters when combined with other cosmological observables. We aim to demonstrate its potential in constraining cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-16 Alessandra Fumagalli , Matteo Costanzi , Alexandro Saro , Tiago Castro , Stefano Borgani

Many models of quintessence predict a time variation of the fundamental constants as well as a composition-dependent gravity like long-range force mediated by the cosmon. We present bounds for the cosmon coupling to matter and radiation…

High Energy Physics - Phenomenology · Physics 2009-11-07 C. Wetterich

In a class of models designed to solve the cosmological constant problem by coupling scalar or tensor classical fields to the space-time curvature, the universal scale factor grows as a power law in the age, $a \propto t^\alpha$, regardless…

Astrophysics · Physics 2016-08-25 M. Kaplinghat , G. Steigman , I. Tkachev , T. P. Walker

We describe scalar-bimetric theories where the dynamics of the Universe are governed by two separate metrics, each with an Einstein-Hilbert term. In this setting, the baryonic and dark matter components of the Universe couple to metrics…

General Relativity and Quantum Cosmology · Physics 2018-10-09 Philippe Brax , Patrick Valageas

Thawing quintessence scalar field models with the various potential forms to explain the late-time cosmic acceleration are compared to the {\Lambda}CDM model in detail by analyzing cosmological parameters with a set of observational data…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 Fereshteh Felegary , Kazuharu Bamba

We propose to use a simple observable, the fractional area of "hot spots" in weak gravitational lensing mass maps which are detected with high significance, to determine background cosmological parameters. Because these high-convergence…

Astrophysics · Physics 2011-02-11 Sheng Wang , Zoltán Haiman , Morgan May

Future large ensembles of time delay lenses have the potential to provide interesting cosmological constraints complementary to those of other methods. In a flat universe with constant w including a Planck prior, LSST time delay…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 Dan Coe , Leonidas Moustakas

Several models within the framework of Einstein-Gauss-Bonnet gravities are considered with regard their late-time phenomenological viability. The models contain a non-minimally coupled scalar field and satisfy a constraint on the scalar…

General Relativity and Quantum Cosmology · Physics 2025-03-25 S. D. Odintsov , V. K. Oikonomou , German S. Sharov

Recently, attempts have been made to understand the apparent near coincidence of the present dark energy and matter energy in terms of a dynamical attractor-like solution for the evolution of a scalar field. In these models the field…

Astrophysics · Physics 2009-11-06 M. Yahiro , G. J. Mathews , K. Ichiki , T. Kajino , M. Orito

Scalar-tensor theories (STTs) are a widely studied alternative to General Relativity (GR) in which gravity is endowed with an additional scalar degree of freedom. Although severely constrained by solar system and pulsar timing experiments,…

General Relativity and Quantum Cosmology · Physics 2015-03-13 Raissa F. P. Mendes

We compute the PPN parameters $\gamma$ and $\beta$ for general scalar-tensor theories in the Einstein frame, which we compare to the existing PPN formulation in the Jordan frame for alternative theories of gravity. This computation is…

General Relativity and Quantum Cosmology · Physics 2014-12-08 Andreas Schärer , Raymond Angélil , Ruxandra Bondarescu , Philippe Jetzer , Andrew Lundgren

We propose a general model where quintessence couples to electromagnetism via its kinetic term. This novelty generalizes the linear dependence of the gauge kinetic function on $\phi$, commonly adopted in the literature. The interaction…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-23 Bruno J. Barros , Vitor da Fonseca

Pulsar-timing has become a celebrated tool for probing modifications to General Relativity in the strong-field surroundings of neutron stars. Here we investigate whether scalar-tensor theories that incorporate a nonminimally coupled scalar…

General Relativity and Quantum Cosmology · Physics 2019-06-19 Raissa F. P. Mendes , Tulio Ottoni

Redshift distortions, both geometrical and kinematical, of quasar clustering are simulated, for the Two-Degree Field QSO Redshift Survey (2QZ), showing that they are very effective to constrain the cosmological density and equation of state…

Astrophysics · Physics 2007-05-23 M. O. Calvao , J. R. T. de Mello Neto , I. Waga