English
Related papers

Related papers: Fractal Structure of Loop Quantum Gravity

200 papers

The seemingly universal phenomenon of scale-dependent effective dimensions in non-perturbative theories of quantum gravity has been shown to be a potential source of quantum gravity phenomenology. The scale-dependent effective dimension…

General Relativity and Quantum Cosmology · Physics 2023-05-16 Marcus Reitz , Dániel Németh , Damodar Rajbhandari , Andrzej Görlich , Jakub Gizbert-Studnicki

We calculate the spectral dimension for a nonperturbative lattice approach to quantum gravity, known as causal dynamical triangulations (CDT), showing that the dimension of spacetime smoothly decreases from approximately 4 on large distance…

High Energy Physics - Theory · Physics 2015-04-21 D. N. Coumbe , J. Jurkiewicz

We reinterpret the spectral dimension of spacetimes as the scaling of an effective self-energy transition amplitude in quantum field theory (QFT), when the system is probed at a given resolution. This picture has four main advantages: (a)…

High Energy Physics - Theory · Physics 2016-04-13 Gianluca Calcagni , Leonardo Modesto , Giuseppe Nardelli

Loop quantum cosmology(LQC) is the symmetric model of loop quantum gravity. In this paper, we generalize the structure of loop quantum cosmology to the theories with arbitrary spacetime dimensions. The isotropic and homogenous cosmological…

General Relativity and Quantum Cosmology · Physics 2016-10-13 Xiangdong Zhang

Borrowing techniques from cosmology, I compute the power spectrum of quantum fluctuations in (2+1)-dimensional causal dynamical triangulations, a promising discrete path integral approach to quantum gravity. The results agree with those of…

General Relativity and Quantum Cosmology · Physics 2011-11-03 Michael K. Sachs

We review the status of understanding of the fractal structure of the quantum spacetime of 2d gravity coupled to conformal matter with c <= 1, with emphasis put on the results obtained last year.

High Energy Physics - Lattice · Physics 2009-10-31 K. N. Anagnostopoulos

The emergence of fractal features in the microscopic structure of space-time is a common theme in many approaches to quantum gravity. In this work we carry out a detailed renormalization group study of the spectral dimension $d_s$ and walk…

High Energy Physics - Theory · Physics 2015-05-30 Martin Reuter , Frank Saueressig

We derive the cutoff length scale of the quadratic gravity in $d \geq 5$ dimensional spacetime by demanding that the quantum focusing conjecture for the smeared quantum expansion holds at the classical level. The cutoff scale has different…

High Energy Physics - Theory · Physics 2024-05-03 Takamasa Kanai , Kengo Maeda , Toshifumi Noumi , Daisuke Yoshida

Quantum gravity is investigated in the limit of a large number of space-time dimensions, using as an ultraviolet regularization the simplicial lattice path integral formulation. In the weak field limit the appropriate expansion parameter is…

High Energy Physics - Theory · Physics 2008-11-26 Herbert W. Hamber , Ruth M. Williams

Quantum-gravity renders the space-time dimension to depend on the size of region; it monotonically increases with the size of region and asymptotically approaches four for large distances. This effect was discovered in numerical simulations…

High Energy Physics - Theory · Physics 2010-02-17 Michael Maziashvili

The phase diagram of 2d Lorentzian quantum gravity (LQG) coupled to conformal matter is studied. A phase transition is observed at $c=c_{\rm crit}$ ($1/2<c_{\rm crit}<4$) which can be thought of as the analogue of the $c=1$ barrier of…

High Energy Physics - Lattice · Physics 2015-06-25 Jan Ambjorn , K. N. Anagnostopoulos , R. Loll

Planck-scale dynamical dimensional reduction is attracting more and more interest in the quantum-gravity literature since it seems to be a model independent effect. However different studies base their results on different concepts of…

General Relativity and Quantum Cosmology · Physics 2016-07-29 Michele Ronco

The aim of this dissertation is to review `Loop Quantum Gravity', explaining the main structure of the theory and indicating its main open issues. We will develop the two main lines of research for the theory: the canonical quantization…

General Relativity and Quantum Cosmology · Physics 2018-08-06 Pablo Antonio Moreno Casares

This papers offers a critical discussion on the procedure by which Loop Quantum Cosmology (LQC) is constructed from the full Loop Quantum Gravity (LQG) theory. Revising recent issues in preserving SU(2) symmetry when quantizing the…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Francesco Cianfrani , Giovanni Montani

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

Understanding the quantum aspects of gravity is not only a matter of equations and experiments. Gravity is intimately connected with the structure of space and time, and understanding quantum gravity requires us to find a conceptual…

General Relativity and Quantum Cosmology · Physics 2022-11-29 Carlo Rovelli , Francesca Vidotto

We adopt a novel approach to combine path integral methods with Loop Quantum Gravity (LQG). Our approach builds upon the recently developed coherent state path integral formulation of LQG to compute the one-loop effective action. We compare…

General Relativity and Quantum Cosmology · Physics 2025-02-12 Renata Ferrero , Muxin Han , Hongguang Liu

We show that in general a spacetime having a quantum group symmetry has also a scale dependent fractal dimension which deviates from its classical value at short scales, a phenomenon that resembles what observed in some approaches to…

High Energy Physics - Theory · Physics 2009-04-08 Dario Benedetti

This Ph.D. thesis pursues two goals: The study of the geometrical structure of two-dimensional quantum gravity and in particular its fractal nature. To address these questions we review the continuum formalism of quantum gravity with…

High Energy Physics - Theory · Physics 2007-05-23 Juri Rolf

One of the celebrated results of Loop Quantum Gravity (LQG) is the discreteness of the spectrum of geometrical operators such as length, area and volume operators. This is an indication that Planck scale geometry in LQG is discontinuous…

General Relativity and Quantum Cosmology · Physics 2009-02-10 Bianca Dittrich , Thomas Thiemann