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We show that long-distance quantum correlations probe short-distance physics. Two disjoint regions of the latticized, massless scalar field vacuum are numerically demonstrated to become separable at distances beyond the negativity sphere,…

High Energy Physics - Theory · Physics 2021-12-01 Natalie Klco , Martin J. Savage

Causal Dynamical Triangulations (CDT) is a methodology to define and compute the gravitational path integral, whose aim is a fully fledged nonperturbative quantum field theory of gravity and spacetime. Analogous to lattice formulations of…

High Energy Physics - Theory · Physics 2026-04-08 J. Ambjørn , R. Loll

We measure the spectral dimension of universes emerging from nonperturbative quantum gravity, defined through state sums of causal triangulated geometries. While four-dimensional on large scales, the quantum universe appears two-dimensional…

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

We investigate the luminosity and redshift dependence of the quasar continuum by means of composite spectrum using a large non-BAL radio-quiet quasar sample drawn from the Sloan Digital Sky Survey. Quasar continuum slopes in the UV-Opt band…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-24 Xiaoyi Xie , Shiyin Shen , Zhengyi Shao , Jun Yin

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

We construct a theory of fields living on continuous geometries with fractional Hausdorff and spectral dimensions, focussing on a flat background analogous to Minkowski spacetime. After reviewing the properties of fractional spaces with…

High Energy Physics - Theory · Physics 2012-01-19 Gianluca Calcagni

We numerically investigate the influence of high-order dispersion on both temporal and spectral characterizations of microresonator-based optical frequency combs. The moment method is utilized to study the temporal dynamics of intracavity…

Optics · Physics 2014-03-04 Shaofei Wang , Hairun Guo , Xuekun Bai , Xianglong Zeng

Dual-comb spectroscopy in the ultraviolet (UV) and visible would enable broad bandwidth electronic spectroscopy with unprecedented frequency resolution. However, there are significant challenges in generation, detection and processing of…

We address the problem of diffusion on a comb whose teeth display a varying length. Specifically, the length $\ell$ of each tooth is drawn from a probability distribution displaying the large-$\ell$ behavior $P(\ell) \sim…

Statistical Mechanics · Physics 2016-08-03 S. B. Yuste , E. Abad , A. Baumgaertner

We study 2D quantum gravity on spherical topologies employing the Regge calculus approach with the dl/l measure. Instead of the normally used fixed non-regular triangulation we study random triangulations which are generated by the standard…

High Energy Physics - Lattice · Physics 2009-10-31 Christian Holm , Wolfhard Janke

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

Recent results suggest that a crucial crossroad for quantum gravity is the characterization of the effective dimension of spacetime at short distances, where quantum properties of spacetime become significant. This is relevant in particular…

High Energy Physics - Theory · Physics 2017-02-01 Giovanni Amelino-Camelia , Francesco Brighenti , Giulia Gubitosi , Grasiele Santos

The optical frequency comb has made a significant impact in precision spectroscopy and on our ability to probe atomic, molecular and, recently, nuclear transitions to further our understanding of their fundamental properties and how their…

Optics · Physics 2026-02-17 John J. McCauley , DylanP. Tooley , R. Jason Jones

We analyze the universal properties of a new two-dimensional quantum gravity model defined in terms of Locally Causal Dynamical Triangulations (LCDT). Measuring the Hausdorff and spectral dimensions of the dynamical geometrical ensemble, we…

High Energy Physics - Theory · Physics 2015-10-07 Renate Loll , Ben Ruijl

We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-19 Mathias Garny , Thomas Konstandin , Rafael A. Porto , Laura Sagunski

The spectrum of the Laplace-Beltrami operator, computed on the spatial slices of Causal Dynamical Triangulations, is a powerful probe of the geometrical properties of the configurations sampled in the various phases of the lattice theory.…

High Energy Physics - Theory · Physics 2019-06-26 Giuseppe Clemente , Massimo D'Elia , Alessandro Ferraro

With the advent of laser frequency combs, coherent light sources that offer equally-spaced sharp lines over a broad spectral bandwidth have become available. One decade after revolutionizing optical frequency metrology, frequency combs hold…

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

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 discuss the possible existence of new generic vacuum solutions of Robertson-Walker form in higher derivative gravity theories in four dimensions. These solutions illustrate how a dynamical coupling between very low and very high…

High Energy Physics - Theory · Physics 2007-05-23 Bob Holdom