National Research University – Higher School of Economics

About: National Research University – Higher School of Economics is a education organization based out in Moscow, Russia. It is known for research contribution in the topics: Population & Computer science. The organization has 12873 authors who have published 23376 publications receiving 256396 citations.

Falsifying Λ CDM : Model-independent tests of the concordance model with eBOSS DR14Q and Pantheon

Abstract: We combine model-independent reconstructions of the expansion history from the latest Pantheon supernovae distance modulus compilation and measurements from baryon acoustic oscillation to test some important aspects of the concordance model of cosmology namely the Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) metric and flatness of spatial curvature. We then use the reconstructed expansion histories to fit growth measurement from redshift-space distortion and obtain constraints on (${\mathrm{\ensuremath{\Omega}}}_{\mathrm{m}}$, $\ensuremath{\gamma}$, ${\ensuremath{\sigma}}_{8}$) in a model independent manner. Our results show consistency with a spatially flat FLRW Universe with general relativity to govern the perturbation in the structure formation and the cosmological constant as dark energy. However, we can also see some hints of tension among different observations within the context of the concordance model related to high redshift observations ($zg1$) of the expansion history. This supports earlier findings of [G.-B. Zhao, Nat. Astron. 1, 627 (2017), V. Sahni, A. Shafieloo, and A. A. Starobinsky, Astrophys. J. 793, L40 (2014)] and highlights the importance of precise measurement of expansion history and growth of structure at high redshifts.

Approaches to the selection of relevant concepts in the case of noisy data

Abstract: Concept lattices built on noisy data tend to be large and hence hard to interpret. We introduce several measures that can be used in selecting relevant concepts and discuss how they can be combined together. We study their performance in a series of experiments.