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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

The standard formulation of the cosmological constant problem is based on one critical assumption---the spacetime is homogeneous and isotropic, which is true only on cosmological scales. However, this problem is caused by extremely small…

General Relativity and Quantum Cosmology · Physics 2020-08-05 Qingdi Wang

We consider three dimensional gravity with a positive cosmological constant and non- zero gravitational Chern-Simons term. This theory has inflating de Sitter solutions and local metric degrees of freedom. The Euclidean signature partition…

High Energy Physics - Theory · Physics 2011-11-23 Alejandra Castro , Nima Lashkari , Alexander Maloney

Within thermodynamic models of gravity, where the universe is considered as a finite ensemble of quantum particles, cosmological constant in the Einstein's equations appears as a constant of integration. Then it can be bounded using…

General Physics · Physics 2018-05-15 Merab Gogberashvili , Ucha Chutkerashvili

We covariantly modify the Einstein-Hilbert action such that the modified action perturbatively resolves the flat rotational velocity curve of the spiral galaxies and gives rise to the Tully-Fisher relation, and dynamically generates the…

General Relativity and Quantum Cosmology · Physics 2011-02-01 Qasem Exirifard

Quantum gravity places important consistency conditions on low-energy effective field theory, such as the absence of global symmetries. These may have important consequences in the search for particle physics beyond the Standard Model. We…

High Energy Physics - Phenomenology · Physics 2022-03-16 Patrick Draper , Isabel Garcia Garcia , Matthew Reece

We study four-dimensional quantum gravity using non-perturbative renormalization group methods. We solve the corresponding equations for the fully momentum-dependent propagator, Newton's coupling and the cosmological constant. For the first…

High Energy Physics - Theory · Physics 2016-02-17 Nicolai Christiansen , Benjamin Knorr , Jan M. Pawlowski , Andreas Rodigast

This article lays out a complete framework for an effective theory of cosmological perturbations with corrections from canonical quantum gravity. Since several examples exist for quantum-gravity effects that change the structure of…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Aurelien Barrau , Martin Bojowald , Gianluca Calcagni , Julien Grain , Mikhail Kagan

We extend the treatment of quantum cosmology to a manifold with torsion. We adopt a model of Einstein-Cartan-Sciama-Kibble compatible with the cosmological principle. The universe wavefunction will be subject to a $\mathcal{PT}$-symmetric…

General Relativity and Quantum Cosmology · Physics 2020-12-22 Ammar Kasem , Shaaban Khalil

Assuming that Quantum Einstein Gravity (QEG) is the correct theory of gravity on all length scales we use analytical results from nonperturbative renormalization group (RG) equations as well as experimental input in order to characterize…

High Energy Physics - Theory · Physics 2009-09-24 M. Reuter , H. Weyer

We re-examine results of the Liouville theory and provide arguments that a {\it negative} bare cosmological constant is essential to define two-dimensional quantum gravity. From this we are naturally led to a regularization of quantum…

High Energy Physics - Lattice · Physics 2007-05-23 Wolfgang Beirl , Bernd A. Berg

We discuss a special class of quantum gravity phenomena that occur on the scale of the Universe as a whole at any stage of its evolution. These phenomena are a direct consequence of the zero rest mass of gravitons, conformal non-invariance…

General Relativity and Quantum Cosmology · Physics 2013-09-03 Leonid Marochnik , Daniel Usikov , Grigory Vereshkov

We present a theory of four-dimensional quantum gravity with massive gravitons which may be essentially renormalizable. In the Plebanski formulation of General Relativity (GR), in which the tetrads, the connection and the curvature are all…

General Relativity and Quantum Cosmology · Physics 2011-11-10 L. V. Laperashvili

In this article the phenomenon of degravitation of the cosmological constant is studied in the framework of bigravity. It is demonstrated that despite a sizable value of the cosmological constant its gravitational effect can be only mild.…

General Relativity and Quantum Cosmology · Physics 2017-04-05 Moritz Platscher , Juri Smirnov

The arguments of statistical nature for the existence of constituents of active gravitational masses are presented. The present paper proposes a basis for microscopic theory of universal gravitation. Questions like the relation of…

High Energy Physics - Theory · Physics 2014-11-18 Pawel O. Mazur

A class of vector-tensor theories arises naturally in the framework of quadratic gravity in spacetimes with linear vector distortion. Requiring the absence of ghosts for the vector field imposes an interesting condition on the allowed…

High Energy Physics - Theory · Physics 2016-05-04 Jose Beltran Jimenez , Lavinia Heisenberg , Tomi S. Koivisto

We estimate the possible variations of the gravitational constant G in the framework of a generalized (Bergmann-Wagoner-Nordtvedt) scalar-tensor theory of gravity on the basis of the field equations, without using their special solutions.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 K. A. Bronnikov , V. N. Melnikov , Mario Novello

In the Batalin - Fradkin - Vilkovisky approach to quantization of gauge theories a principal role is given to the BRST charge which can be constructed as a series in Grassmannian (ghost) variables with coefficients given by generalized…

General Relativity and Quantum Cosmology · Physics 2015-04-09 T. P. Shestakova

Within the framework of the minimum quadratic Poincare gauge theory of gravity in the Riemann-Cartan spacetime we study the influence of gravitational vacuum energy density (a cosmological constant) on the dynamics of various gravitating…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Nguyen Hong Chuong , Nguyen Van Hoang

We investigate the effect of a cosmological constant on the gravothermal catastrophe in the Newtonian limit. A negative cosmological constant acts as a thermodynamic `destabilizer'. The Antonov radius gets smaller and the instability…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-05 Minos Axenides , George Georgiou , Zacharias Roupas