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Causal Dynamical Triangulations (CDT) provide a non-perturbative formulation of Quantum Gravity assuming the existence of a global time foliation. In our earlier study we analyzed the effect of including $d$ copies of a massless scalar…

General Relativity and Quantum Cosmology · Physics 2015-04-15 Jan Ambjørn , Andrzej Görlich , Jerzy Jurkiewicz , Hongguang Zhang

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

Lattice formulations of gravity can be used to study non-perturbative aspects of quantum gravity. Causal Dynamical Triangulations (CDT) is a lattice model of gravity that has been used in this way. It has a built-in time foliation but is…

General Relativity and Quantum Cosmology · Physics 2021-03-30 J. Ambjorn , Z. Drogosz , J. Gizbert-Studnicki , A. Görlich , J. Jurkiewicz , D. Nèmeth

The observable universe has undergone periods of expansion that are well approximated by de Sitter (dS) space. Still lacking is a quantum mechanical description of dS, both globally and when restricted to the static patch. We develop a…

High Energy Physics - Theory · Physics 2025-08-15 Vyshnav Mohan , Watse Sybesma

"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

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 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

We study the geometries generated by two-dimensional causal dynamical triangulations (CDT) coupled to $d$ massless scalar fields. Using methods similar to those used to study four-dimensional CDT we show that there exists a $c=1$ "barrier",…

General Relativity and Quantum Cosmology · Physics 2015-06-03 J. Ambjorn , A. T. Goerlich , J. Jurkiewicz , H. -G. Zhang

We perform a minisuperspace analysis of an information-theoretic nonlinear Wheeler-deWitt (WDW) equation for de Sitter universes. The nonlinear WDW equation, which is in the form of a difference-differential equation, is transformed into a…

General Relativity and Quantum Cosmology · Physics 2012-04-02 Rajesh R. Parwani , Siti Nursaba Tarih

Detailed applications of minisuperspace methods are presented and compared with results obtained in recent years by means of causal dynamical triangulations (CDTs), mainly in the form of effective actions. The analysis sheds light on…

General Relativity and Quantum Cosmology · Physics 2020-01-09 Bekir Baytas , Martin Bojowald , Sean Crowe , Jakub Mielczarek

A dynamical aspect of quantum gravity on de Sitter spacetime is investigated by holography or the dS/CFT correspondence. We show that de Sitter spacetime emerges from a free Sp(N) vector model by complexifying the ghost fields and flowing…

High Energy Physics - Theory · Physics 2020-04-10 Shuichi Yokoyama

Causal dynamical triangulations (CDT) constitute a background independent, nonperturbative approach to quantum gravity, in which the gravitational path integral is approximated by the weighted sum over causally well-behaving simplicial…

High Energy Physics - Theory · Physics 2011-02-24 T. Trzesniewski

Understanding the continuum limit of a theory of discrete random geometries is a beautiful but difficult challenge. In this optic, we review here the insights that can be obtained for Causal Dynamical Triangulations (CDT) by employing the…

High Energy Physics - Theory · Physics 2025-01-09 Dario Benedetti

We provide a hands-on introduction to Monte Carlo simulations in nonperturbative lattice quantum gravity, formulated in terms of Causal Dynamical Triangulations (CDT). We describe explicitly the implementation of Monte Carlo moves and the…

High Energy Physics - Theory · Physics 2023-10-26 Joren Brunekreef , Andrzej Görlich , Renate Loll

There has been strong interest in the possibility that in the quantum-gravity realm momentum space might be curved, mainly focusing, especially for what concerns phenomenological implications, on the case of a de Sitter momentum space. We…

General Relativity and Quantum Cosmology · Physics 2024-03-26 Giovanni Amelino-Camelia , Iarley P. Lobo , Giovanni Palmisano

Causal Dynamical Triangulations is a background independent approach to quantum gravity. We show that there exists an effective transfer matrix labeled by the scale factor which properly describes the evolution of the quantum universe. In…

High Energy Physics - Theory · Physics 2013-02-13 Andrzej Görlich

Generalized causal dynamical triangulations (generalized CDT) is a model of two-dimensional quantum gravity in which a limited number of spatial topology changes is allowed to occur. We solve the model at the discretized level using…

High Energy Physics - Theory · Physics 2013-07-22 Jan Ambjorn , Timothy G. Budd

This paper continues the investigation of constant mean curvature (CMC) time functions in maximal globally hyperbolic spatially compact spacetimes of constant sectional curvature, which was started in math.DG/0604486. In that paper, the…

Differential Geometry · Mathematics 2007-05-23 Lars Andersson , Thierry Barbot , Francois Beguin , Abdelghani Zeghib

The theory of causal dynamical triangulations (CDT) attempts to define a nonperturbative theory of quantum gravity as a sum over space-time geometries. One of the ingredients of the CDT framework is a global time foliation, which also plays…

High Energy Physics - Theory · Physics 2014-11-20 J. Ambjorn , A. Gorlich , S. Jordan , J. Jurkiewicz , R. Loll

In the Emergent scenario, the Universe should evolve from a non-singular state replacing the typical singularity of General Relativity, for any initial condition. For the scalar field model in [1] we show that only a set of measure zero of…

General Relativity and Quantum Cosmology · Physics 2024-08-13 Molly Burkmar , Marco Bruni