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We study continuous time quantum walk on a random comb graph with infinite teeth. Due to localization effects along the spine, the walk cannot go to infinity in the spine direction, while it can escape to infinity along the teeth of the…

量子物理 · 物理学 2026-04-02 François David , Thordur Jonsson

The Causal Dynamical Triangulation model of quantum gravity (CDT) has a transfer matrix, relating spatial geometries at adjacent (discrete lattice) times. The transfer matrix uniquely determines the theory. We show that the measurements of…

高能物理 - 理论 · 物理学 2016-02-10 Jan Ambjorn , Jakub Gizbert-Studnicki , Andrzej Görlich , Jerzy Jurkiewicz

In this Near Intermediate-Scale Quantum era, there are two types of near-term quantum devices available on cloud: superconducting quantum processing units (QPUs) based on the discrete variable model and linear optics (photonics) QPUs based…

量子物理 · 物理学 2022-06-16 Sophie Choe

We demonstrate that local, scale-dependent non-Gaussianity can generate cosmic variance uncertainty in the observed spectral index of primordial curvature perturbations. In a universe much larger than our current Hubble volume, locally…

宇宙学与河外天体物理 · 物理学 2015-06-16 Joseph Bramante , Jason Kumar , Elliot Nelson , Sarah Shandera

Optical frequency combs have the potential to improve the precision of the radial velocity measurement of celestial bodies, leading to breakthroughs in such fields as exoplanet exploration. For these purposes, the comb must have a broad…

天体物理仪器与方法 · 物理学 2023-06-06 Keisuke Nakamura , Ken Kashiwagi , Sho Okubo , Hajime Inaba

We outline a field theory on a multifractal spacetime. The measure in the action is characterized by a varying Hausdorff dimension and logarithmic oscillations governed by a fundamental physical length. A fine hierarchy of length scales…

高能物理 - 理论 · 物理学 2011-09-29 Gianluca Calcagni

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…

高能物理 - 理论 · 物理学 2021-04-12 Alberto Salvio

Among the many disparate approaches towards quantum gravity, the reduction of spacetime dimension in the ultraviolet regime is expected to be a common thread. The dimensionality of spacetime can be defined in various contexts. The spectral…

广义相对论与量子宇宙学 · 物理学 2022-04-26 Vikramaditya Mondal

We study the average number of simplices $N'(r)$ at geodesic distance $r$ in the dynamical triangulation model of euclidean quantum gravity in four dimensions. We use $N'(r)$ to explore definitions of curvature and of effective global…

高能物理 - 格点 · 物理学 2009-10-22 Bas V. de Bakker , Jan Smit

The spectra of random feature matrices provide essential information on the conditioning of the linear system used in random feature regression problems and are thus connected to the consistency and generalization of random feature models.…

机器学习 · 统计学 2022-12-13 Zhijun Chen , Hayden Schaeffer , Rachel Ward

Development of the optical frequency comb has revolutionised metrology and precision spectroscopy due to its ability to provide a precise and direct link between microwave and optical frequencies. A novel application of frequency comb…

Hints from a number of different approaches to quantum gravity point to a phenomenon of "spontaneous dimensional reduction" to two spacetime dimensions near the Planck scale. I examine the physical meaning of the term "dimension" in this…

广义相对论与量子宇宙学 · 物理学 2016-11-15 S. Carlip

The relation between the results of cosmological N-body simulations, and the continuum theoretical models they simulate, is currently not understood in a way which allows a quantification of N dependent effects. In this first of a series of…

天体物理学 · 物理学 2013-05-29 Michael Joyce , Bruno Marcos

Measurements of the Hubble constant, and more generally measurements of the expansion rate and distances over the interval $0 < z < 1$, appear to be inconsistent with the predictions of the standard cosmological model ($\Lambda$CDM) given…

宇宙学与河外天体物理 · 物理学 2020-03-04 Lloyd Knox , Marius Millea

By applying the Covariant Entropy Bound (CEB) to an EFT in a box of size $1/\Lambda_{\text{IR}}$ one obtains that the UV and IR cut-offs of the EFT are necessarily correlated. We argue that in a theory of Quantum Gravity (QG) one should…

高能物理 - 理论 · 物理学 2022-09-07 Alberto Castellano , Alvaro Herráez , Luis E. Ibáñez

We investigate the behavior of small subsets of causal sets that approximate Minkowski space in three, four, and five dimensions, and show that their effective dimension decreases smoothly at small distances. The details of the short…

广义相对论与量子宇宙学 · 物理学 2018-03-14 J. Abajian , S. Carlip

Random tensor models can be used as combinatorial devices to generate Euclidean dynamical triangulations. A physical continuum limit of dynamical triangulations requires a suitable generalization of the double-scaling limit of random…

广义相对论与量子宇宙学 · 物理学 2026-02-11 Alicia Castro , Astrid Eichhorn , Razvan Gurau

We investigate the cause of the divergence of the entanglement entropy for the free scalar fields in $(1+1)$ and $(D + 1)$ dimensional space-times. In a canonically equivalent set of variables, we show explicitly that the divergence in the…

高能物理 - 理论 · 物理学 2014-09-02 Krishnanand Mallayya , Rakesh Tibrewala , S. Shankaranarayanan , T. Padmanabhan

Different types of two- and three-dimensional representations of a finite metric space are studied that focus on the accurate representation of the linear order among the distances rather than their actual values. Lower and upper bounds for…

组合数学 · 数学 2007-05-23 Jobst Heitzig

We present evidence that a nonperturbative model of quantum gravity defined via Euclidean dynamical triangulations contains a region in parameter space with an extended 4-dimensional geometry when a non-trivial measure term is included in…

高能物理 - 格点 · 物理学 2012-04-05 Daniel Coumbe , Jack Laiho