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The standard model of cosmology assumes that the Universe can be described to hover around a homogeneous-isotropic solution of Einstein's general theory of relativity. This description needs (sometimes hidden) hypotheses that restrict the…

General Relativity and Quantum Cosmology · Physics 2018-12-21 Thomas Buchert

We show that vector theories on cosmological scales are excellent candidates for dark energy. We consider two different examples, both are theories with no dimensional parameters nor potential terms, with natural initial conditions in the…

Astrophysics · Physics 2015-05-13 Jose Beltran Jimenez , Antonio L. Maroto

The origin of the observed acceleration of the expansion of the universe is a major problem of modern cosmology and theoretical physics. Simple estimations of the contribution of vacuum to the density energy of the universe in quantum field…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-11 Arnaud Dupays , Brahim Lamine , Alain Blanchard

I argue that a solution to the cosmological constant problem is to assume that the expectation value of the quantum vacuum stress-energy tensor is proportional to the metric tensor with a negative energy density and positive pressure. This…

General Physics · Physics 2018-05-09 Emilio Santos

The early cosmic inflation, when taken along with the recent observations that the universe is currently dominated by a low density vacuum energy, leads to at least two potential problems which modern cosmology must address. First, there is…

Astrophysics · Physics 2009-11-07 Manasse R. Mbonye

A central aspect of the cosmological constant problem is to understand why vacuum energy does not gravitate. In order to account for this observation, while allowing for nontrivial dynamics of the quantum vacuum, we motivate a novel…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Stephon Alexander , Raúl Carballo-Rubio

It will be argued here that the cosmological constant problem exists because of the way the vacuum is defined in quantum field theory. It has been known for some time that for QFT to be gauge invariant certain terms--such as part of the…

General Relativity and Quantum Cosmology · Physics 2008-06-20 Gerald E. Marsh

The work shows that the associated Einstein like gravity for the Klein-Gordon field shows the spontaneous emergence of the cosmological pressure tensor density (CPTD) that in the classical limit leads to the cosmological constant (CC). Even…

General Physics · Physics 2020-07-07 Piero Chiarelli

In this paper we provide both a diagnosis and resolution of the cosmological constant problem, one in which a large (as opposed to a small) cosmological constant $\Lambda$ can be made compatible with observation. We trace the origin of the…

Astrophysics · Physics 2009-10-31 Philip D. Mannheim

We generalize tensor-scalar theories of gravitation by the introduction of an abnormally weighting type of energy. This theory of tensor-scalar anomalous gravity is based on a relaxation of the weak equivalence principle that is now…

Astrophysics · Physics 2009-01-14 J. -M. Alimi , A. Füzfa

The general thermodynamic analysis of the quantum vacuum, which is based on our knowledge of the vacua in condensed-matter systems, is consistent with the Einstein earlier view on the cosmological constant. In the equilibrium Universes the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 G. E. Volovik

The value of the cosmological constant is explained in terms of a noisy diffusion of energy from the low energy particle physics degrees of freedom to the fundamental Planckian granularity which is expected from general arguments in quantum…

General Relativity and Quantum Cosmology · Physics 2018-12-19 Alejandro Perez , Daniel Sudarsky , James D. Bjorken

The accelerating expansion of the Universe points to a small positive value for the cosmological constant or vacuum energy density. We discuss recent ideas that the cosmological constant plus LHC results might hint at critical phenomena…

High Energy Physics - Phenomenology · Physics 2015-07-09 Steven D. Bass

We show that quantum decoherence, in the context of observational cosmology, can be connected to the cosmic dark energy. The decoherence signature could be characterized by the existence of quantum entanglement between cosmological eras. As…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Salvatore Capozziello , Orlando Luongo

We address issues on the origin of gravity and the cosmological constant problem based on a recent understanding about the correspondence between noncommutative field theory and gravity. We suggest that the cosmological constant problem can…

High Energy Physics - Theory · Physics 2008-03-28 Hyun Seok Yang

In this paper, time variable cosmological constant, dubbed {\it age cosmological constant}, is investigated motivated by the fact: any cosmological length scale and time scale can introduce a cosmological constant or vacuum energy density…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-28 Lixin Xu , Jianbo Lu , Wenbo Li

The cosmological constant (CC) term in Einstein's equations, Lambda, was first associated to the idea of vacuum energy density. Notwithstanding, it is well-known that there is a huge, in fact appalling, discrepancy between the theoretical…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Joan Sola

In this work we consider quantum electromagnetic fields in an expanding universe. We start by reviewing the difficulties found when trying to impose the Lorenz condition in a time-dependent geometry. Motivated by this fact, we explore the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Jose Beltran Jimenez , Antonio L. Maroto

In this paper we calculate quantum corrections to the effective potential in different models of inflationary cosmology. We show that quantum corrections lead to a modification of the initial potential uplifting its value at the minimum,…

High Energy Physics - Theory · Physics 2025-04-16 V. A. Filippov , R. M. Iakhibbaev , D. I. Kazakov , D. M. Tolkachev

The cosmological constant, i.e., the energy density stored in the true vacuum state of all existing fields in the Universe, is the simplest and the most natural possibility to describe the current cosmic acceleration. However, despite its…

Astrophysics · Physics 2008-11-26 S. Carneiro , M. A. Dantas , C. Pigozzo , J. S. Alcaniz
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