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We define a new scaling limit of matrix models which can be related to the method of causal dynamical triangulations (CDT) used when investigating two-dimensional quantum gravity. Surprisingly, the new scaling limit of the matrix models is…

High Energy Physics - Theory · Physics 2008-12-18 J. Ambjorn , R. Loll , Y. Watabiki , W. Westra , S. Zohren

We investigate the interaction between matter and causal dynamical triangulations (CDT) in the context of two-dimensional quantum gravity. We focus on the Ising model coupled to CDT, contrasting this with Liouville gravity and the relation…

High Energy Physics - Theory · Physics 2025-05-09 Ryan Barouki , Henry Stubbs , John Wheater

Causal Dynamical Triangulations (CDT) is a lattice theory of quantum gravity. It is shown how to identify the IR and the UV limits of this lattice theory with similar limits studied using the continuum, functional renormalization group…

High Energy Physics - Lattice · Physics 2025-09-26 Jan Ambjorn , Jakub Gizbert-Studnicki , Andrzej Goerlich , Daniel Nemeth

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

A recently conjectured relashionship between UV and IR cutoffs in an effective field theory without quantum gravity is generalized in the presence of large extra dimensions. Estimates for the corrections to the usual calculation of…

High Energy Physics - Phenomenology · Physics 2009-10-31 José Luis Cortés

We adopt a framework where quantum-gravity's dynamical dimensional reduction of spacetime at short distances is described in terms of modified dispersion relations. We observe that by subjecting such models to a momentum-space…

General Relativity and Quantum Cosmology · Physics 2013-09-17 Giovanni Amelino-Camelia , Michele Arzano , Giulia Gubitosi , Joao Magueijo

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

We propose that the effective dimensionality of the space we live in depends on the length scale we are probing. As the length scale increases, new dimensions open up. At short scales the space is lower dimensional; at the intermediate…

High Energy Physics - Phenomenology · Physics 2015-05-18 Luis Anchordoqui , De Chang Dai , Malcolm Fairbairn , Greg Landsberg , Dejan Stojkovic

Causal dynamical triangulations (CDT) can be used as a regularization of quantum gravity. In two dimensions the theory can be solved anlytically, even before the cut-off is removed and one can study in detail how to take the continuum…

High Energy Physics - Theory · Physics 2014-11-20 J. Ambjorn , R. Loll , Y. Watabiki , W. Westra , S. Zohren

By means of the present geometrical and dynamical observational data, it is very hard to establish, from a statistical perspective, a clear preference among the vast majority of the proposed models for the dynamical dark energy and/or…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-07 Tomasz Denkiewicz , Vincenzo Salzano

We investigate the spectral dimension obtained from non-local continuum d'Alembertians derived from causal sets. We find a universal dimensional reduction to 2 dimensions, in all dimensions. We conclude by discussing the validity and…

General Relativity and Quantum Cosmology · Physics 2016-02-17 Alessio Belenchia , Dionigi M. T. Benincasa , Antonino Marciano , Leonardo Modesto

We extend the definition of "spectral dimension" (usually defined for fractal and lattice geometries) to theories on smooth spacetimes with anisotropic scaling. We show that in quantum gravity dominated by a Lifshitz point with dynamical…

High Energy Physics - Theory · Physics 2009-06-16 Petr Horava

There is a growing evidence that due to quantum gravity effects the effective spacetime dimensionality might change in the UV. In this letter we investigate this hypothesis by using quantum fields to derive the UV behaviour of the static,…

High Energy Physics - Theory · Physics 2017-05-24 Michele Arzano , Jerzy Kowalski-Glikman

This article discusses the infrared and the (perspective) ultraviolet limits of four-dimensional Causal Dynamical Triangulations (CDT). CDT is a non-perturabtive and background-independent approach to quantization of Einstein's gravity,…

High Energy Physics - Theory · Physics 2023-01-18 Jakub Gizbert-Studnicki

There are several studies proposing phenomenological consequences of a deformation of special and general relativity. Here, we cast novel constraints on the deformation parameter of a metric in the cotangent bundle accounting for a curved…

General Relativity and Quantum Cosmology · Physics 2020-11-18 J. J. Relancio , S. Liberati

We study the continuum limit of a "radially reduced" approximation of Causal Dynamical Triangulations (CDT), so-called multigraph ensembles, and explain why they serve as realistic toy models to study the dimensional reduction observed in…

High Energy Physics - Theory · Physics 2013-02-15 Georgios Giasemidis , John F. Wheater , Stefan Zohren

Cavity-enhanced direct frequency comb spectroscopy combines broad spectral bandwidth, high spectral resolution, precise frequency calibration, and ultrahigh detection sensitivity, all in one experimental platform based on an optical…

Optics · Physics 2009-11-13 Michael J. Thorpe , Jun Ye

This thesis investigates low-dimensional models of nonperturbative quantum gravity, with a special focus on Causal Dynamical Triangulations (CDT). We define the so-called curvature profile, a new quantum gravitational observable based on…

General Relativity and Quantum Cosmology · Physics 2023-11-14 Joren Brunekreef

We construct a family of measures for random fields based on the iterated subdivision of simple geometric shapes (triangles, squares, tetrahedrons) into a finite number of similar shapes. The intent is to construct continuum limits of scale…

High Energy Physics - Theory · Physics 2012-07-05 Arnab Kar , S. G. Rajeev

The four dimensional Causal Dynamical Triangulations (CDT) approach to quantum gravity is already more than ten years old theory with numerous unprecedented predictions such as non-trivial phase structure of gravitational field and…

General Relativity and Quantum Cosmology · Physics 2015-12-31 Jakub Mielczarek