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相关论文: Renyi entropy as a measure of cosmic homogeneity

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We analyze a set of volume limited sample of galaxies from the SDSS to study the issue of cosmic homogeneity. We use the Renyi entropy of different order to probe the inhomogeneties present in the galaxy distributions. We also calculate the…

宇宙学与河外天体物理 · 物理学 2021-07-21 Biswajit Pandey , Suman Sarkar

We propose a method for testing cosmic homogeneity based on the Shannon entropy in Information theory and test the potentials and limitations of the method on Monte Carlo simulations of some homogeneous and inhomogeneous 3D point process in…

宇宙学与河外天体物理 · 物理学 2015-06-12 Biswajit Pandey

We propose a novel method for testing isotropy of a three-dimensional distribution using Shannon entropy. We test the method on some Monte Carlo simulations of isotropic and anisotropic distributions and find that the method can effectively…

宇宙学与河外天体物理 · 物理学 2016-08-24 Biswajit Pandey

The Cosmological Principle posits that the Universe is isotropic on the largest scales. While widely supported, this foundational assumption remains testable. We analyse the angular distribution of over one million quasars from the…

宇宙学与河外天体物理 · 物理学 2025-07-04 Amit Mondal , Biswajit Pandey , Krishna Ghosh

We propose a method to probe the homogeneity of a general universe, without assuming symmetry. We show that isotropy can be tested at remote locations on the past lightcone by comparing the line-of-sight and transverse expansion rates,…

宇宙学与河外天体物理 · 物理学 2019-06-05 Raul Jimenez , Roy Maartens , Ali Rida Khalifeh , Robert R. Caldwell , Alan F. Heavens , Licia Verde

Using the 2MASS Photometric Redshift catalogue we perform a number of statistical tests aimed at detecting possible departures from statistical homogeneity and isotropy in the large-scale structure of the Universe. Making use of the angular…

宇宙学与河外天体物理 · 物理学 2015-06-23 David Alonso , Ana Isabel Salvador , Francisco Javier Sánchez , Maciej Bilicki , Juan García-Bellido , Eusebio Sánchez

General relations are found between the measure of the uniformity of distributions on the phase space and the first moments and correlations of extensive variables for systems close to thermal equilibrium. The role played by the parameter…

统计力学 · 物理学 2009-11-07 Arkadiusz Majka , Wojciech Wislicki

We study the possibility of detecting the transition to homogeneity using photometric redshift catalogs. Our method is based on measuring the fractality of the projected galaxy distribution, using angular distances, and relies only on…

宇宙学与河外天体物理 · 物理学 2014-03-05 D. Alonso , A. Bueno Belloso , F. J. Sánchez , J. García-Bellido , E. Sánchez

We test the homogeneity of the Universe at $z\sim 0.3$ with the Luminous Red Galaxy (LRG) spectroscopic sample of the Sloan Digital Sky Survey. First, the mean number $N(R)$ of LRGs within completely surveyed LRG-centered spheres of…

In this study, we probe the cosmic homogeneity with the BOSS CMASS galaxy sample in the redshift region of $0.43 < z < 0.7$. We use the normalised counts-in-spheres estimator $\mathcal{N}(<r)$ and the fractal correlation dimension…

宇宙学与河外天体物理 · 物理学 2016-07-13 Pierros Ntelis

We introduce an information-theoretic measure, the Renyi information, to describe the galaxy distribution in space. We discuss properties of the information measure, and demonstrate its relationship with the probability distribution…

天体物理学 · 物理学 2010-11-11 Fan Fang

We analyze a set of volume limited samples from SDSS DR12 to quantify the degree of inhomogeneity at different length scales using Shannon entropy. We find that the galaxy distributions exhibit a higher degree of inhomogeneity as compared…

宇宙学与河外天体物理 · 物理学 2015-10-21 Biswajit Pandey , Suman Sarkar

We review observational tests for the homogeneity of the Universe on large scales. Redshift and peculiar velocity surveys, radio sources, the X-Ray Background, the Lyman-alpha forest and the Cosmic Microwave Background are used to set…

天体物理学 · 物理学 2016-08-30 Ofer Lahav

We quantify the degree of inhomogeneity in the Luminous Red Galaxy (LRG) distribution from the SDSS DR7 as a function of length scales by measuring the Shannon entropy in independent and regular cubic voxels of increasing grid sizes. We…

宇宙学与河外天体物理 · 物理学 2016-05-25 Biswajit Pandey , Suman Sarkar

We calculate the quantum Renyi entropy in a phase space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate…

其他凝聚态物理 · 物理学 2015-05-28 Laura E. C. Rosales-Zárate , P. D. Drummond

We propose a new field theoretic method for calculating Renyi entropy of a sub-system of many interacting Bosons without using replica methods. This method is applicable to dynamics of both open and closed quantum systems starting from…

统计力学 · 物理学 2021-12-14 Ahana Chakraborty , Rajdeep Sensarma

In standard cosmology, the cosmic homogeneity scale is the transition scale above which the patterns arising from non-uniformities -- such as groups and clusters of galaxies, voids, and filaments -- become indistinguishable from a random…

宇宙学与河外天体物理 · 物理学 2025-10-09 Xiaoyun Shao , Rodrigo S. Gonçalves , Carlos A. P. Bengaly , Uendert Andrade , Gabriela C. Carvalho , Jailson Alcaniz

The BOSS quasar sample is used to study cosmic homogeneity with a 3D survey in the redshift range $2.2<z<2.8$. We measure the count-in-sphere, $N(<\! r)$, i.e. the average number of objects around a given object, and its logarithmic…

The standard model of cosmology is based on the existence of homogeneous surfaces as the background arena for structure formation. Homogeneity underpins both general relativistic and modified gravity models and is central to the way in…

宇宙学与河外天体物理 · 物理学 2015-03-19 Roy Maartens

We discuss some properties of the generalized entropies, called Renyi entropies and their application to the case of continuous distributions. In particular it is shown that these measures of complexity can be divergent, however, their…

无序系统与神经网络 · 物理学 2007-05-23 I. Varga , J. Pipek
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