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Related papers: From Causal Dynamical Triangulations To Astronomic…

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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

We discuss some problems related to dimensional reductions of gravity theories to two-dimensional and one-dimensional dilaton gravity models. We first consider the most general cylindrical reductions of the four-dimensional gravity and…

High Energy Physics - Theory · Physics 2007-05-23 A. T. Filippov

We study the implications of the simplicity constraint in the spincube model of quantum gravity. By relating the edge-lengths to the integer areas of triangles, the simplicity constraint imposes very strong restrictions between them,…

General Relativity and Quantum Cosmology · Physics 2016-08-03 Marko Vojinovic

Causal Dynamical Triangulations (CDT), a candidate theory of nonperturbative quantum gravity in 4D, turns out to have a rich phase structure. We investigate the recently discovered bifurcation phase $C_b$ and relate some of its…

High Energy Physics - Theory · Physics 2017-04-05 J. Ambjørn , J. Gizbert-Studnicki , A. Görlich , J. Jurkiewicz , N. Klitgaard , R. Loll

We perform a non-perturbative sum over geometries in a (2+1)-dimensional quantum gravity model given in terms of Causal Dynamical Triangulations. Inspired by the concept of triangulations of product type introduced previously, we impose an…

High Energy Physics - Theory · Physics 2008-11-26 D. Benedetti , R. Loll , F. Zamponi

We focus on mesoscopic dislocation patterning via a continuum dislocation dynamics theory (CDD) in three dimensions (3D). We study three distinct physically motivated dynamics which consistently lead to fractal formation in 3D with rather…

Statistical Mechanics · Physics 2015-03-19 Yong S. Chen , Woosong Choi , Stefanos Papanikolaou , Matthew Bierbaum , James P. Sethna

Quantum gravity phenomenology has been historically regarded as a difficult endeavour, due to the apparent scarcity of phenomena involving the required scales of length (Planck length $l_P$) and energy (Planck energy $E_P$). It was…

High Energy Physics - Phenomenology · Physics 2023-10-10 Andrea Bevilacqua , Jerzy Kowalski-Glikman , Wojciech Wislicki

The causal dynamical triangulations (CDT) program has for the first time allowed for path-integral computation of correlation functions in full general relativity without symmetry reductions and taking into account Lorentzian signature. One…

General Relativity and Quantum Cosmology · Physics 2010-12-23 R L Maitra

We discuss the nature of quantum field theories involving gravity that are classically scale-invariant. We show that gravitational radiative corrections are crucial in the determination of the nature of the vacuum state in such theories,…

High Energy Physics - Theory · Physics 2015-03-18 Martin B. Einhorn , D. R. Timothy Jones

In this work, we use the dynamical system approach to explore the cosmological background evolution of the scalar-tensor representation of $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the stress-energy tensor. The…

General Relativity and Quantum Cosmology · Physics 2024-04-04 Tiago B. Gonçalves , João Luís Rosa , Francisco S. N. Lobo

We review (and extend) the analysis of general theories of all interactions (gravity included) where the mass scales are due to dimensional transmutation. Quantum consistency requires the presence of terms in the action with four…

High Energy Physics - Theory · Physics 2021-04-12 Alberto Salvio

We study the phase diagram of a one-dimensional balls-in-boxes (BIB) model that has been proposed as an effective model for the spatial-volume dynamics of (2+1)-dimensional causal dynamical triangulations (CDT). The latter is a statistical…

High Energy Physics - Theory · Physics 2017-05-02 Dario Benedetti , James P. Ryan

We study random walks on ensembles of a specific class of random multigraphs which provide an "effective graph ensemble" for the causal dynamical triangulation (CDT) model of quantum gravity. In particular, we investigate the spectral…

High Energy Physics - Theory · Physics 2012-09-25 Georgios Giasemidis , John F. Wheater , Stefan Zohren

In this paper, we develop a theory of redshift distortion of the galaxy power spectrum in the discrete wavelet transform (DWT) representation. Because the DWT power spectrum is dependent of both the scale and shape (configuration) of the…

Astrophysics · Physics 2009-11-07 Xiao-Hu Yang , Long-Long Feng , Yao-Quan Chu , Li-Zhi Fang

We derive the dynamics of (isotropic) scalar perturbations from the mean-field hydrodynamics of full Lorentzian quantum gravity, as described by a two-sector (timelike and spacelike) Barrett-Crane group field theory (GFT) model. The rich…

General Relativity and Quantum Cosmology · Physics 2024-04-02 Alexander F. Jercher , Luca Marchetti , Andreas G. A. Pithis

We study the Causal Dynamical Triangulation (CDT) with extended interactions in 1+1 dimensions applying the method in the non-critical string field theory (SFT) constructed by Ishibashi and Kawai. For this model, we solve Schwinger-Dyson's…

High Energy Physics - Theory · Physics 2015-05-30 Hiroyuki Fuji , Yuki Sato , Yoshiyuki Watabiki

We advocate lattice methods as the tool of choice to constructively define a background-independent theory of Lorentzian quantum gravity and explore its physical properties in the Planckian regime. The formulation that arguably has most…

High Energy Physics - Lattice · Physics 2011-05-30 J. Ambjorn , J. Jurkiewicz , R. Loll

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

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

The recent measurements of Cosmic Microwave Background temperature and polarization anisotropies made by the Planck satellite have provided impressive confirmation of the $\Lambda$CDM cosmological model. However interesting hints of slight…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Eleonora Di Valentino , Alessandro Melchiorri , Joseph Silk