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This is the third paper in a series of four in which we use space adiabatic methods in order to incorporate backreactions among the homogeneous and between the homogeneous and inhomogeneous degrees of freedom in quantum cosmological…

General Relativity and Quantum Cosmology · Physics 2019-06-20 S. Schander , T. Thiemann

Quantum theory of the gravitation in the causal approach is studied up to the second order of perturbation theory. We prove gauge invariance and renormalizability in the second order of perturbation theory for the pure gravity system…

High Energy Physics - Theory · Physics 2010-01-06 Dan Radu Grigore

In a large variety of quantum mechanical systems, we show that the full non-perturbative expression for energy eigenvalues, containing all orders of perturbative, non-perturbative and quasi-zero-mode terms, may be generated directly from…

High Energy Physics - Theory · Physics 2014-04-04 Gerald V. Dunne , Mithat Unsal

One of the biggest challenges to theoretical physics of our time is to find a background-independent quantum theory of gravity. Today one encounters a profusion of different attempts at quantization, but no fully accepted - or acceptable,…

General Relativity and Quantum Cosmology · Physics 2008-01-29 M. D. Iftime

We suggest a version of renormalizable Quantum Field Theory which does not contain non-perturbative effects. This is otained by the proper use of the boundary conditions in the functional integral of the generating functional of Green…

General Physics · Physics 2024-12-17 S. A. Larin

The subject of the first section-lecture is concerned with the strength and the weakness of the perturbation theory (PT) approach, that is expansion in powers of a small parameter $\alpha$, in Quantum Theory. We start with outlining a…

High Energy Physics - Phenomenology · Physics 2012-03-05 Alexander P. Bakulev , Dmitry V. Shirkov

Using stochastic quantization method we derive gauge-invariant equations, connecting multilocal vacuum correlators of nonperturbative field configurations immersed into the quantum background. Three alternative methods of stochastic…

High Energy Physics - Theory · Physics 2007-05-23 D. V. Antonov

We propose a new formalism for quantum field theory which is neither based on functional integrals, nor on Feynman graphs, but on marked trees. This formalism is constructive, i.e. it computes correlation functions through convergent rather…

High Energy Physics - Theory · Physics 2015-05-13 R. Gurau , J. Magnen , V. Rivasseau

We provide a mechanism by which, from a background independent model with no quantum mechanics, quantum theory arises in the same limit in which spatial properties appear. Starting with an arbitrary abstract graph as the microscopic model…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Fotini Markopoulou , Lee Smolin

We show that after the Seiberg-Witten map is performed the action for noncommutative field theories can be regarded as a coupling to a field dependent gravitational background. This gravitational background depends only on the gauge field.…

High Energy Physics - Theory · Physics 2009-11-07 Victor O. Rivelles

The aim of this paper is to explain carefully the arguments behind the assertion that the correct quantum theory of gravity must be background independent. We begin by recounting how the debate over whether quantum gravity must be…

High Energy Physics - Theory · Physics 2007-05-23 Lee Smolin

The cosmological stochastic gravitational-wave background produced by the mildly non-linear evolution of density fluctuations is analyzed, in the frame of an Einstein-de Sitter model, by means of a fully relativistic perturbation expansion…

Astrophysics · Physics 2007-05-23 Sabino Matarrese , Silvia Mollerach

The quantum field theory of gravitation is constructed in terms of Lagrangian density of Dirac fields which couple to the electromagnetic field $A_\mu$ as well as the gravitational field $\cal G$. The gravity appears in the mass term as $…

General Physics · Physics 2008-04-17 Takehisa Fujita

We recast the action principle of four dimensional General Relativity so that it becomes amenable for perturbation theory which doesn't break general covariance. The coupling constant becomes dimensionless (G_{Newton} \Lambda) and extremely…

High Energy Physics - Theory · Physics 2007-05-23 Laurent Freidel , Artem Starodubtsev

The problem of background independent quantum gravity is the problem of defining a quantum field theory of matter and gravity in the absence of an underlying background geometry. Loop quantum gravity (LQG) is a promising proposal for…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Alejandro Perez

We present a method of constructing perturbative equations of motion for the geometric background of any given tensorial field theory. Requiring invariance of the gravitational dynamics under spacetime diffeomorphisms leads to a PDE system…

General Relativity and Quantum Cosmology · Physics 2019-09-04 Tobias Reinhart , Nils Alex

Is there an approach to quantum gravity which is conceptually simple, relies on very few fundamental physical principles and ingredients, emphasizes geometric (as opposed to algebraic) properties, comes with a definite numerical…

General Relativity and Quantum Cosmology · Physics 2008-11-26 R. Loll

Black hole perturbation theory beyond second order is not well understood because typically one defines the meaning of gauge invariance order by order which is ambiguous. In this series of works we therefore developed a new approach which…

General Relativity and Quantum Cosmology · Physics 2026-02-10 Jonas Neuser , Thomas Thiemann

We develop a new technique for studying the perturbations of dRGT-type massive gravity theories around arbitrary background spacetimes. Built initially from the vielbein formulation of the theory, but switching back to the metric…

High Energy Physics - Theory · Physics 2025-11-25 Kieran Wood

We study the nonlinear gravitational dynamics of a universe filled with a pressureless fluid and a cosmological constant $\Lambda$ in the context of Newtonian gravity, and in the relativistic post-Friedmann approach proposed in paper I [I.…

General Relativity and Quantum Cosmology · Physics 2016-10-26 Cornelius Rampf , Eleonora Villa , Daniele Bertacca , Marco Bruni