English
Related papers

Related papers: Cosmological Constant in a Quantum Gravity Theory …

200 papers

We review the approach to quantum gravity which is based on the assumption that the short-distance structure of the spacetime is given by a piecewise flat manifold corresponding to a triangulation of a smooth manifold. We then describe the…

General Relativity and Quantum Cosmology · Physics 2025-01-03 Aleksandar Mikovic

We show that scale invariance provides a solution to the fine tuning problem of the cosmological constant. We construct a generalization of the standard model of particle physics which displays exact quantum scale invariance. The matter…

High Energy Physics - Phenomenology · Physics 2011-02-02 Pankaj Jain , Subhadip Mitra , Sukanta Panda , Naveen K. Singh

The method of four-dimensional Causal Dynamical Triangulations provides a background-independent definition of the sum over geometries in quantum gravity, in the presence of a positive cosmological constant. We present the evidence…

High Energy Physics - Theory · Physics 2007-05-23 J. Ambjorn , J. Jurkiewicz , R. Loll

We have recently presented a manifestly local and general coordinate invariant formulation of a nonlocal approach to the cosmological constant problem which has been proposed by Carroll and Remmen. In this article, based on our formulation,…

High Energy Physics - Theory · Physics 2017-07-26 Ichiro Oda

Prominent approaches to quantum gravity struggle when it comes to incorporating a positive cosmological constant in their models. Using quantization of a complex $\mathrm{SL}(2,\mathbb{C})$ Chern-Simons theory we include a cosmological…

High Energy Physics - Theory · Physics 2015-12-09 Hal M. Haggard , Muxin Han , Wojciech Kamiński , Aldo Riello

In quantum field theory the parameters of the vacuum action are subject to renormalization group running. In particular, the ``cosmological constant'' is not a constant in a quantum field theory context, still less should be zero. In this…

High Energy Physics - Theory · Physics 2009-10-31 Ilya L. Shapiro , Joan Sola

This paper is a generalization of earlier papers [Nucl. Phys. B 884, 344 (2014) (arXiv:1312.2759) and JHEP 6, 63 (2015) (arXiv:1401.2488)]. We generalize the idea of quantum clock time to quantum spacetime reference frame via physical…

General Relativity and Quantum Cosmology · Physics 2018-03-20 M. J. Luo

In the present article, which is the first part of a work in three parts, we build an equation of quantum gravity. This equation is tensorial, is equivalent to general relativity in vacuum, but differs completely from general relativity…

General Physics · Physics 2007-11-25 Christophe Real

When the cosmological constant of spacetime is derived from the 5D induced-matter theory of gravity, we show that a simple gauge transformation changes it to a variable measure of the vacuum which is infinite at the big bang and decays to…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Bahram Mashhoon , Paul S. Wesson

An one-parameter regularization freedom of the Hamiltonian constraint for loop quantum gravity is analyzed. The corresponding spatially flat, homogenous and isotropic model includes the two well-known models of loop quantum cosmology as…

General Relativity and Quantum Cosmology · Physics 2021-11-12 Xiangdong Zhang , Gaoping Long , Yongge Ma

A quantum field theory formalism is reviewed that leads to a self-consistent, finite quantum gravity, Yang-Mills and Higgs theory, which is unitary and gauge invariant to all orders of perturbation theory. The gauge hierarchy problem is…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. W. Moffat

Unimodular gravity addresses the old cosmological constant (CC) problem, explaining why such constant is not at least as large as the largest particle mass scale, but classically it is indistinguishable from ordinary gravity. Conversely,…

High Energy Physics - Theory · Physics 2024-08-05 Alberto Salvio

The cosmological implications of the Covariant Canonical Gauge Theory of Gravity (CCGG) are investigated. We deduce that, in a metric compatible geometry, the requirement of covariant conservation of matter invokes torsion of space-time. In…

General Relativity and Quantum Cosmology · Physics 2024-10-28 David Vasak , Johannes Kirsch , Juergen Struckmeier

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

There are many theories of quantum gravity, depending on asymptotic boundary conditions, and the amount of supersymmetry. The cosmological constant is one of the fundamental parameters that characterize different theories. If it is…

High Energy Physics - Theory · Physics 2015-06-26 T. Banks

We examine the general issue of whether a scale dependent cosmological constant can be consistent with general covariance, a problem that arises naturally in the treatment of quantum gravitation where coupling constants generally run as a…

High Energy Physics - Theory · Physics 2015-06-12 Herbert W. Hamber , Reiko Toriumi

We revisit the proposal that the resolution of the Cosmological Constant Problem involves a sub-millimeter breakdown of the point-particle approximation for gravitons. No fundamental description of such a breakdown, which simultaneously…

High Energy Physics - Theory · Physics 2009-09-15 Raman Sundrum

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

A unique feature of gravity is its ability to control the information accessible to any specific observer. We quantify the notion of cosmic information ('CosmIn') for an eternal observer in the universe. Demanding the finiteness of CosmIn…

General Relativity and Quantum Cosmology · Physics 2017-08-28 T. Padmanabhan , Hamsa Padmanabhan

We study a Newtonian cosmological model in the context of a noncommutative space. It is shown that the trajectories of a test particle undergo modifications such that it no longer satisfies the cosmological principle. For the case of a…

High Energy Physics - Theory · Physics 2010-11-05 Juan M. Romero , J. A. Santiago