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The values of the fundamental constants such as $\mu = m_P/m_e$, the proton to electron mass ratio and $\alpha$, the fine structure constant, are sensitive to the product $\sqrt{\zeta_x^2(w+1)}$ where $\zeta_x$ is a coupling constant…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-19 Rodger I. Thompson

The sum of cosmic neutrino masses can be measured cosmologically, as the sub-eV particles behave as `hot' dark matter whose main effect is to suppress the clustering of matter compared to a universe with the same amount of purely cold dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-05 Helen Shao , Jahmour J. Givans , Jo Dunkley , Mathew Madhavacheril , Frank Qu , Gerrit Farren , Blake Sherwin

We present a new class of non-singular string cosmologies in d space-time dimensions. At very early times, \tau << \tau_c, the Universe is described by a flat \sigma-model metric, a constant maximal temperature T_c and super-weak string…

High Energy Physics - Theory · Physics 2015-06-03 Costas Kounnas , Herve Partouche , Nicolaos Toumbas

We present technical results which extend previous work and show that the cosmological constant of general relativity is an artefact of the reduction to 4D of 5D Kaluza-Klein theory (or 10D superstrings and 11D supergravity). We argue that…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Paul S. Wesson , Hongya Liu

We study the impact of the symmetry breaking patterns from supersymmetric SO(10) down to the standard model on the standard big-bang cosmology through the formation of topological defects. None of the models is consistent with the standard…

High Energy Physics - Phenomenology · Physics 2010-11-01 Rachel Jeannerot , Anne-Christine Davis

The current standard model of cosmology - the {\ensuremath{\Lambda}}CDM model - is appropriately named after its controversial foreign ingredients: a cosmological constant ({\ensuremath{\Lambda}}) that accounts for the recent accelerated…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-26 Elsa M. Teixeira

In this essay, we present a new understanding of the cosmological constant problem, built upon the realization that the vacuum energy density can be expressed in terms of a phase space volume. We introduce a UV-IR regularization which…

High Energy Physics - Theory · Physics 2023-03-31 Laurent Freidel , Jerzy Kowalski-Glikman , Robert G. Leigh , Djordje Minic

The strong equivalence principle is extended in application to averaged dynamical fields in cosmology to include the role of the average density in the determination of inertial frames. The resulting cosmological equivalence principle is…

General Relativity and Quantum Cosmology · Physics 2008-11-26 David L. Wiltshire

The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in…

General Relativity and Quantum Cosmology · Physics 2016-11-14 Cláudio Nassif

We argue that supersymmetry breaking by gaugino condensation in the strongly coupled heterotic string can be described by an analogue of Scherk-Schwarz compactification on the eleventh dimension in M-theory. The M-theory scale is identified…

High Energy Physics - Theory · Physics 2009-10-30 I. Antoniadis , M. Quiros

Any Dark Energy (DE) or Modified Gravity (MG) model that deviates from a cosmological constant requires a consistent treatment of its perturbations, which can be described in terms of an effective entropy perturbation and an anisotropic…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-26 Bjoern Soergel , Tommaso Giannantonio , Jochen Weller , Richard A. Battye

The comparison of the Standard Cosmological Model (SCM) with astronomical observations, i.e. theory versus experiment, and with the Minimal Standard Model (MSM) in particle physics, i.e. theory versus theory, is discussed. The main issue of…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. D. Dolgov

In a recent model of dark energy (with several phenomenological consequences), the universe is assumed to be trapped in a false vacuum with an energy density of the order of (10^{-3} eV)^4, mimicking the presently successful $\Lambda CDM$…

High Energy Physics - Phenomenology · Physics 2007-11-29 P. Q. Hung

We elaborate on the recently proposed static brane world scenario, where the effective 4-D cosmological constant is exponentially small when parallel 3-branes are far apart. We extend this result to a compactified model with two positive…

High Energy Physics - Theory · Physics 2009-10-31 Eanna Flanagan , Nicholas Jones , Horace Stoica , S. -H. Henry Tye , Ira Wasserman

In a recent paper (Vigoureux et al. Int. J. Theor. Phys. 47:928, 2007) it has been suggested that the velocity of light and the expansion of the universe are two aspects of one single concept connecting space and time in the expanding…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-22 David Viennot , Jean-Marie Vigoureux

We introduce a symmetry principle that forbids a bulk cosmological constant in six and ten dimensions. Then the symmetry is extended so that it insures absence of 4-dimensional cosmological constant induced by the six dimensional curvature…

High Energy Physics - Theory · Physics 2009-11-10 Recai Erdem

In the early-mid 20$^{\rm th}$ century Dirac and Zel'dovich were among the first scientists to suggest an intimate connection between cosmology and atomic physics. Though a revolutionary proposal for its time, Dirac's Large Number…

General Relativity and Quantum Cosmology · Physics 2017-12-08 Matthew J. Lake

This is the first paper of a series devoted to the study of the cosmological implications of the parallel mirror world with the same microphysics as the ordinary one, but having smaller temperature, with a limit set by the BBN constraints.…

Astrophysics · Physics 2008-11-26 P. Ciarcelluti

In this paper we study the description of the Universe based on the low energy superstring theory modified by the Loop Quantum Gravity effects.This approach was proposed by De Risi et al. in the Phys. Rev. D {\bf 76} (2007) 103531. We show…

High Energy Physics - Theory · Physics 2008-11-26 Jakub Mielczarek , Marek Szydlowski

Supersymmetric unification in warped space provides new possibilities for model building. I argue that the picture of warped supersymmetric unification arises naturally through the AdS/CFT correspondence from the assumption that…

High Energy Physics - Phenomenology · Physics 2007-05-23 Yasunori Nomura