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We investigate the gravitational property of the quantum vacuum by treating its large energy density predicted by quantum field theory seriously and assuming that it does gravitate to obey the equivalence principle of general relativity. We…

General Relativity and Quantum Cosmology · Physics 2019-04-22 Qingdi Wang , Zhen Zhu , William G. Unruh

An alternative cosmological model is presented, which avoids the requirement of dark energy and dark matter. Based on the proposition that energy conservation should be valid not only locally but also globally, the energy tensor of general…

General Physics · Physics 2007-08-30 Ernst Fischer

We investigate a cosmological model in which the Stueckelberg fields are non-minimally coupled to the scalar curvature in a gauge invariant manner. We present not only a solution that can be considered in the context of the late time…

General Relativity and Quantum Cosmology · Physics 2014-07-04 Ozgur Akarsu , Metin Arik , Nihan Katirci , Mehmet Kavuk

Within the framework of a model universe with time variable space dimension (TVSD), known as decrumpling or TVSD model, we show the present value of the deceleration parameter is negative implying that the universe is accelerating today.…

High Energy Physics - Theory · Physics 2007-05-23 Forough Nasseri

The aim of this paper is to show, that the 'oscillating universe' is a viable alternative to inflation. We remind that this model provides a natural solution to the flatness or entropy and to the horizon problem of standard cosmology. We…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Ruth Durrer , Joachim Laukenmann

In the present mainstream cosmology, matter and spacetime emerged from a singularity and evolved through four distinct periods: early inflation, radiation, dark matter and late-time inflation (driven by dark energy). During the radiation…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-02 E. L. D. Perico , J. A. S. Lima , Spyros Basilakos , Joan Sola

We study the possibility that the current accelerated expansion of the universe is driven by the vacuum energy density of a colored scalar field which is responsible for a phase transition in which the gauge SU(3)_c symmetry breaks. We show…

High Energy Physics - Phenomenology · Physics 2008-11-26 Dejan Stojkovic , Glenn D. Starkman , Reijiro Matsuo

Cosmological models with inflation and those with bounce have their own strengths and weaknesses. Here we construct a model in which a phase of bounce is followed by a viable inflationary phase. This incorporates several advantages of both…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-02 Manjeet Kaur , Debottam Nandi , Debajyoti Choudhury , T. R. Seshadri

Recent observations of Type Ia supernovae provide evidence for the acceleration of our universe, which leads to the possibility that the universe is entering an inflationary epoch. We simulate it under a ``big bounce'' model, which contains…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Beili Wang , Hongya Liu , Lixin Xu

We explore a collapsing cosmology driven by a scalar field which is minimally coupled to gravity in a spatially at and spherically symmetric, isotropic and homogeneous space-time, with a variable timescale that avoids the final singularity.…

General Relativity and Quantum Cosmology · Physics 2021-05-07 Jaime M. Hernandez , Mauricio Bellini , Claudia Moreno

In [1], KKLT give a mechanism to generate de Sitter vacua in string theory. And the scenario, \emph{Landscape}, is suggested to explain the problem of the cosmological constant. In this paper, adopting a simple potential describing the…

High Energy Physics - Theory · Physics 2007-05-23 Cheng-Yi Sun , De-Hai Zhang

Dynamical scanning of the Higgs mass by an axion-like particle during inflation may provide a cosmological component to explaining part of the hierarchy problem. We propose a novel interplay of this cosmological relaxation mechanism with…

High Energy Physics - Phenomenology · Physics 2017-09-20 Tevong You

In the Standard Model, the Higgs potential allows only one minimum at tree-level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable…

High Energy Physics - Phenomenology · Physics 2013-11-07 A. Barroso , P. M. Ferreira , I. P. Ivanov , Rui Santos , João P. Silva

Positive vacuum energy together with extra dimensions of space imply that our four-dimensional Universe is unstable, generically to decompactification of the extra dimensions. Either quantum tunneling or thermal fluctuations carry one past…

High Energy Physics - Theory · Physics 2009-11-10 Steven B. Giddings , Robert C. Myers

An oscillating universe cycles through a series of expansions and contractions. We propose a model in which ``phantom'' energy with a supernegative pressure ($p < - \rho$) grows rapidly and dominates the late-time expanding phase. The…

Astrophysics · Physics 2008-03-29 Katherine Freese , Matthew G. Brown , William H. Kinney

Inflation, a period of exponential expansion in the early Universe, is considered an important part of the standard $\Lambda$CDM cosmological model, and plays a crucial role in explaining a wide range of current observations. The standard…

General Relativity and Quantum Cosmology · Physics 2023-12-08 Maria Pia Piccirilli , Gabriel Leon

We study late-time acceleration scenarios using a quintessence field initially trapped in a metastable false vacuum state. The false vacuum has non-zero vacuum energy and could drive exponential expansion if not coupled with gravity. Upon…

General Relativity and Quantum Cosmology · Physics 2025-04-29 Pradosh Keshav M. V. , Arun Kenath

Recently, we have proposed a definition for the vacuum and suggest a mechanism for symmetry breaking. In this mechanism extra massless fields, vacuum fields, arise. We apply our method to the standard model of particle physics and obtain…

High Energy Physics - Phenomenology · Physics 2017-09-15 Ahmad Mohamadnejad

It is a mystery why the density of matter and the density of vacuum energy are nearly equal today when they scale so differently during the expansion of the Universe. We suggest a paradigm that might allow for a non-anthropic solution to…

Astrophysics · Physics 2009-11-07 Kim Griest

Cosmologists have long wondered whether the Universe will eventually re-collapse and end with a Big Crunch, or expand forever, becoming increasingly cold and empty. Recent evidence for a flat Universe, possibly with a cosmological constant…

Astrophysics · Physics 2009-11-07 Robert R. Caldwell , Marc Kamionkowski , Nevin N. Weinberg