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Semiclassical stochastic gravity is aimed at studying extended structure formation in the early universe. Rigorous developments in this area include the semiclassical noise and dissipation kernels which are obtained in terms of quantum…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Seema Satin

We give a derivation of the Einstein equation for gravity which employs a definition of the local energy density of the gravitational field as a symmetric second rank tensor whose value for each observer gives the trace of the spatial part…

Mathematical Physics · Physics 2008-03-13 Maurice J. Dupre

We derive a "classical-quantum" approximation scheme for a broad class of bipartite quantum systems from fully quantum dynamics. In this approximation, one subsystem evolves via classical equations of motion with quantum corrections, and…

Quantum Physics · Physics 2023-06-05 Viqar Husain , Irfan Javed , Sanjeev S. Seahra , Nomaan X

The principle of equivalence provides a description of gravity in terms of the metric tensor and determines how gravity affects the light cone structure of the space-time. This, in turn, leads to the existence of observers (in any…

High Energy Physics - Theory · Physics 2007-05-23 T. Padmanabhan , Apoorva Patel

A recent proposal equates the circuit complexity of a quantum gravity state with the gravitational action of a certain patch of spacetime. Since Einstein's equations follow from varying the action, it should be possible to derive them by…

High Energy Physics - Theory · Physics 2018-01-24 Bartlomiej Czech

In this talk, I present a theory of quantum gravity beyond Einstein. The theory is established based on spinnic and scaling gauge symmetries by treating the gravitational force on the same footing as the electroweak and strong forces. A…

High Energy Physics - Theory · Physics 2015-11-04 Yue-Liang Wu

This paper introduces several ideas of emergent gravity, which come from a system similar to an ensemble of quantum spin-$\tfrac{1}{2}$ particles. To derive a physically relevant theory, the model is constructed by quantizing a scalar field…

General Relativity and Quantum Cosmology · Physics 2024-05-07 Quentin Ansel

It is shown that if the Euclidean path integral measure of a minimally coupled free quantum scalar field on a classical metric background is interpreted as probability of observing the field configuration given the background metric then…

Quantum Physics · Physics 2021-02-22 Can Gokler

Gravitation, according to General Relativity, is an attribute of space-time's geometry and hence not a force in the Newtonian sense. This is a consequence of Einstein's equivalence principle, which so far passed all experimental tests with…

Popular Physics · Physics 2013-09-10 Domenico Giulini

We consider the classical stochastic fluctuations of spacetime geometry induced by quantum fluctuations of massless non-conformal matter fields in the Early Universe. To this end, we supplement the stress-energy tensor of these fields with…

General Relativity and Quantum Cosmology · Physics 2008-11-26 E. Calzetta , A. Campos , E. Verdaguer

Boson stars have been extensively studied in classical gravity, but their quantum properties remain comparatively unexplored. In this paper, we compute the quantum scalar fields and stress tensor in boson star spacetimes within the…

General Relativity and Quantum Cosmology · Physics 2026-01-09 Paul M. Saffin , Qi-Xin Xie

We present a semiclassical gravity in the framework of the double scale theory, a new interpretation of quantum mechanics which expands on the de Broglie-Bohm (dBB) theory. In this interpretation, any quantum system is associated with two…

General Physics · Physics 2023-02-23 Michel Gondran , Alexandre Gondran

We emphasize that a specific aspect of quantum gravity is the absence of a super-selection rule that prevents a linear superposition of different gravitational charges. As an immediate consequence, we obtain a tiny, but observable,…

General Relativity and Quantum Cosmology · Physics 2008-11-26 G. Z. Adunas , E. Rodriguez-Milla , D. V. Ahluwalia

The averaging problem in general relativity is briefly discussed. A new setting of the problem as that of macroscopic description of gravitation is proposed. A covariant space-time averaging procedure is described. The structure of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Roustam M. Zalaletdinov

A broad class of generalized Einstein's gravity can be cast into Einstein's gravity with a minimally coupled scalar field using suitable conformal rescaling of the metric. Using this conformal equivalence between the theories, we derive the…

General Relativity and Quantum Cosmology · Physics 2011-09-30 J. Hwang

A new direction to understand gravity has recently been explored by considering classical gravity to be a derived interaction from an underlying theory. This underlying theory would involve new degrees of freedom at a deeper level and it…

General Physics · Physics 2014-03-10 Yuan K. Ha

Within loop quantum gravity we construct a coarse-grained approximation for the Einstein-Maxwell theory that yields effective Maxwell equations in flat spacetime comprising Planck scale corrections. The corresponding Hamiltonian is defined…

High Energy Physics - Theory · Physics 2009-11-07 Jorge Alfaro , Hugo A. Morales-Técotl , Luis F. Urrutia

This paper explores stability of the Einstein universe against linear homogeneous perturbations in the background of $f(\mathcal{G},T)$ gravity. We construct static as well as perturbed field equations and investigate stability regions for…

General Relativity and Quantum Cosmology · Physics 2017-07-26 M. Sharif , Ayesha Ikram

The semiclassical approximation has frequently been used to describe the initial stage of particle production, often called preheating, which occurs after the inflationary epoch in chaotic models of inflation. During this phase backreaction…

General Relativity and Quantum Cosmology · Physics 2012-11-02 Paul R. Anderson , Carmen Molina-Paris , Dillon H. Sanders

A defining signature of classical systems is "in principle measurability" without disturbance: a feature manifestly violated by quantum systems. We describe a multi-interferometer experimental setup that can, in principle, reveal the…

General Relativity and Quantum Cosmology · Physics 2024-10-30 Farhan Hanif , Debarshi Das , Jonathan Halliwell , Dipankar Home , Anupam Mazumdar , Hendrik Ulbricht , Sougato Bose