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We present a detailed analysis of a recently introduced version of Causal Dynamical Triangulations (CDT) that does not rely on a distinguished time slicing. Focussing on the case of 2+1 spacetime dimensions, we analyze its geometric and…

High Energy Physics - Theory · Physics 2013-09-04 S. Jordan , R. Loll

The formalism of causal dynamical triangulations (CDT) provides us with a non-perturbatively defined model of quantum gravity, where the sum over histories includes only causal space-time histories. Path integrals of CDT and their continuum…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. Ambjorn , R. Loll , W. Westra , S. Zohren

In these lectures we describe how a theory of quantum gravity may be constructed in terms of a lattice formulation based on so-called causal dynamical triangulations (CDT). We discuss how the continuum limit can be obtained and how to…

High Energy Physics - Theory · Physics 2010-07-16 J. Ambjorn , A. Goerlich , J. Jurkiewicz , R. Loll

Quantum Ricci curvature has been introduced recently as a new, geometric observable characterizing the curvature properties of metric spaces, without the need for a smooth structure. Besides coordinate invariance, its key features are…

High Energy Physics - Theory · Physics 2018-05-30 N. Klitgaard , R. Loll

We describe the motivation behind the recent formulation of a nonperturbative path integral for Lorentzian quantum gravity defined through Causal Dynamical Triangulations (CDT). In the case of two dimensions the model is analytically…

High Energy Physics - Theory · Physics 2007-05-23 S. Zohren

Causal Dynamical Triangulations is a non-perturbative quantum gravity model, defined with a lattice cut-off. The model can be viewed as defined with a proper time but with no reference to any three-dimensional spatial background geometry.…

High Energy Physics - Theory · Physics 2019-06-26 Jan Ambjørn , Zbigniew Drogosz , Jakub Gizbert-Studnicki , Andrzej Görlich , Jerzy Jurkiewicz

Geometrical properties of spacetime are difficult to study in nonperturbative approaches to quantum gravity like Causal Dynamical Triangulations (CDT), where one uses simplicial manifolds to define the gravitational path integral, instead…

High Energy Physics - Theory · Physics 2024-06-06 Agustín Silva , Jesse van der Duin

3+1 dimensional Causal Dynamical Triangulations (CDT) describe a quantum theory of fluctuating geometries without the introduction of a background geometry. If the topology of space is constrained to be that of a three-dimensional torus we…

High Energy Physics - Theory · Physics 2017-09-13 Jan Ambjørn , Jakub Gizbert-Studnicki , Andrzej Görlich , Kevin Grosvenor , Jerzy Jurkiewicz

Building on the recently introduced notion of quantum Ricci curvature and motivated by considerations in nonperturbative quantum gravity, we advocate a new, global observable for curved metric spaces, the curvature profile. It is obtained…

General Relativity and Quantum Cosmology · Physics 2021-02-03 J. Brunekreef , R. Loll

"Causal Dynamical Triangulations" (CDT) represent a lattice regularization of the sum over spacetime histories, providing us with a non-perturbative formulation of quantum gravity. The ultraviolet fixed points of the lattice theory can be…

High Energy Physics - Theory · Physics 2015-06-15 J. Ambjorn , A. Goerlich , J. Jurkiewicz , R. Loll

We introduce a generalized version of the Causal Dynamical Triangulations (CDT) formulation of quantum gravity, in which the regularized, triangulated path integral histories retain their causal properties, but do not have a preferred…

High Energy Physics - Theory · Physics 2013-08-28 S. Jordan , R. Loll

Motivated by the search for geometric observables in nonperturbative quantum gravity, we define a notion of coarse-grained Ricci curvature. It is based on a particular way of extracting the local Ricci curvature of a smooth Riemannian…

High Energy Physics - Theory · Physics 2018-02-21 N. Klitgaard , R. Loll

We argue that theories of quantum gravity constructed with the help of (Causal) Dynamical Triangulations have given us the most informative, quantitative models to date of quantum spacetime. Most importantly, these are derived dynamically…

High Energy Physics - Theory · Physics 2015-06-15 J. Ambjorn , S. Jordan , J. Jurkiewicz , R. Loll

Causal Dynamical Triangulations (CDT) is a proposal for a theory of quantum gravity, which implements a path-integral quantization of gravity as the continuum limit of a sum over piecewise flat spacetime geometries. We use Monte Carlo…

High Energy Physics - Theory · Physics 2012-06-25 J. Ambjorn , S. Jordan , J. Jurkiewicz , R. Loll

Previous work has shown that the macroscopic structure of the theory of quantum gravity defined by causal dynamical triangulations (CDT) is compatible with that of a de Sitter universe. After emphasizing the strictly nonperturbative nature…

High Energy Physics - Theory · Physics 2011-05-09 J. Ambjorn , A. Gorlich , J. Jurkiewicz , R. Loll , J. Gizbert-Studnicki , T. Trzesniewski

It is shown that generalized CDT, the two-dimensional theory of quantum gravity, constructed as a scaling limit from so-called causal dynamical triangulations, can be obtained from a cubic matrix model. It involves taking a new scaling…

High Energy Physics - Theory · Physics 2011-06-01 Jan Ambjorn

We search for a continuum limit in the causal dynamical triangulation (CDT) approach to quantum gravity by determining the change in lattice spacing using two independent methods. The two methods yield similar results that may indicate how…

High Energy Physics - Theory · Physics 2016-05-25 Jan Ambjorn , Daniel Coumbe , Jakub Gizbert-Studnicki , Jerzy Jurkiewicz

Four-dimensional CDT (causal dynamical triangulations) is a lattice theory of geometries which one might use in an attempt to define quantum gravity non-perturbatively, following the standard procedures of lattice field theory. Being a…

High Energy Physics - Theory · Physics 2020-03-19 J. Ambjorn , D. Coumbe , J. Gizbert-Studnicki , A. Görlich , J. Jurkiewicz

In this thesis we analyze a very simple model of two dimensional quantum gravity based on causal dynamical triangulations (CDT). We present an exactly solvable model which indicates that it is possible to incorporate spatial topology…

High Energy Physics - Theory · Physics 2008-10-07 Willem Westra

Quantum Gravity by Causal Dynamical Triangulation has over the last few years emerged as a serious contender for a nonperturbative description of the theory. It is a nonperturbative implementation of the sum-over-histories, which relies on…

High Energy Physics - Theory · Physics 2010-04-05 J. Ambjorn , J. Jurkiewicz , R. Loll