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We provide detailed evidence for the claim that nonperturbative quantum gravity, defined through state sums of causal triangulated geometries, possesses a large-scale limit in which the dimension of spacetime is four and the dynamics of the…

High Energy Physics - Theory · Physics 2010-04-06 J. Ambjorn , J. Jurkiewicz , 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

If gravity is asymptotically safe, operators will exhibit anomalous scaling at the ultraviolet fixed point in a way that makes the theory effectively two-dimensional. A number of independent lines of evidence, based on different approaches…

General Relativity and Quantum Cosmology · Physics 2019-04-10 S. Carlip

We introduce a new model for investigating spectral properties of quantum graphs, a quantum circulant graph. Circulant graphs are the Cayley graphs of cyclic groups. Quantum circulant graphs with standard vertex conditions maintain…

Mathematical Physics · Physics 2019-06-21 JM Harrison , E Swindle

A model of simplicial quantum gravity in three dimensions(3D) was investigated numerically based on the technique of dynamical triangulation (DT). We are concerned with the genus of surfaces appearing on boundaries (i.e., sections) of a 3D…

High Energy Physics - Lattice · Physics 2009-10-30 H. S. Egawa , N. Tsuda

Causal Dynamical Triangulations (CDT) is a non-perturbative lattice approach to quantum gravity where one assumes space-time foliation into spatial hyper-surfaces of fixed topology. Most of the CDT results were obtained for the spatial…

High Energy Physics - Theory · Physics 2019-12-03 Jakub Gizbert-Studnicki

Upper bounds of the Hausdorff volume of scalar gradient field graphs are derived by means of geometric measure theory. The approach reproduces that scalar gradient fields along a mean imposed scalar gradient become space filling for…

Chaotic Dynamics · Physics 2009-11-10 Joerg Schumacher

Numerous approaches to quantum gravity report a reduction in the number of spacetime dimensions at the Planck scale. However, accepting the reality of dimensional reduction also means accepting its consequences, including a variable speed…

High Energy Physics - Theory · Physics 2015-10-13 Daniel Coumbe

Many dynamic networks coming from real-world contexts are link streams, i.e. a finite collection of triplets $(u,v,t)$ where $u$ and $v$ are two nodes having a link between them at time $t$. A very large number of studies on these objects…

Social and Information Networks · Computer Science 2018-05-17 Yannick Léo , Christophe Crespelle , Eric Fleury

Classic measures of graph centrality capture distinct aspects of node importance, from the local (e.g., degree) to the global (e.g., closeness). Here we exploit the connection between diffusion and geometry to introduce a multiscale…

Physics and Society · Physics 2020-07-29 Alexis Arnaudon , Robert L. Peach , Mauricio Barahona

We consider a discrete model of euclidean quantum gravity in four dimensions based on a summation over random simplicial manifolds. The action used is the Einstein-Hilbert action plus an $R^2$-term. The phase diagram as a function of the…

High Energy Physics - Theory · Physics 2009-10-22 J. Ambjorn , J. Jurkiewicz , C. F. Kristjansen

The fractal dimension $\delta_g^{(1)}$ of turbulent passive scalar signals is calculated from the fluid dynamical equation. $\delta_g^{(1)}$ depends on the scale. For small Prandtl (or Schmidt) number $Pr<10^{-2}$ one gets two ranges,…

chao-dyn · Physics 2009-10-22 Siegfried Grossmann , Detlef Lohse

This article gives a comprehensive description of the fractal geometry of conformally-invariant (CI) scaling curves, in the plane or half-plane. It focuses on deriving critical exponents associated with interacting random paths, by…

Mathematical Physics · Physics 2007-05-23 Bertrand Duplantier

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

We present a model of (modified) gravity on spacetimes with fractal structure based on packing of spheres, which are (Euclidean) variants of the Packed Swiss Cheese Cosmology models. As the action functional for gravity we consider the…

General Relativity and Quantum Cosmology · Physics 2016-05-25 Adam Ball , Matilde Marcolli

In this paper a new graph invariant based on the minimal hitting set problem is introduced. It is shown that it represents a tight lower bound for the doubly metric dimension of a graph. Exact values of new invariant for paths, stars,…

Combinatorics · Mathematics 2023-10-11 Jozef Kratica , Vera Kovačević-Vujčić , Mirjana Čangalović

We establish the conditions under which scalable spin squeezing can be achieved in interacting spin ensembles embedded in arbitrary, inhomogeneous graph geometries. We identify two different forms of squeezing: OAT-like scalable squeezing…

Quantum Physics · Physics 2026-05-26 Andrea Solfanelli , Augusto Smerzi , Peter Zoller , Nicolò Defenu

In several approaches towards a quantum theory of gravity, such as group field theory and loop quantum gravity, quantum states and histories of the geometric degrees of freedom turn out to be based on discrete spacetime. The most pressing…

General Relativity and Quantum Cosmology · Physics 2018-08-01 Johannes Thürigen

In quantum gravity, several approaches have been proposed until now for the quantum description of discrete geometries. These theoretical frameworks include loop quantum gravity, causal dynamical triangulations, causal sets, quantum…

General Relativity and Quantum Cosmology · Physics 2015-09-14 Ginestra Bianconi , Christoph Rahmede

This work revisits the Euclidean Dynamical Triangulation (DT) approach to non-perturbative quantum gravity in three dimensions. Inspired by a recent combinatorial study by T. Budd and L. Lionni of a subclass of 3-sphere triangulations…

High Energy Physics - Lattice · Physics 2025-09-26 Timothy Budd , Dániel Németh