Персона: Рубин, Сергей Георгиевич
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Руководитель научной группы "Гравитация и космология"
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Рубин
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Сергей Георгиевич
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31 results
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- ПубликацияТолько метаданныеCosmological baryon/lepton asymmetry in terms of Kaluza-Klein extra dimensions(2021) Nikulin, V. V.; Rubin, S. G.; Никулин, Валерий Владимирович; Рубин, Сергей Георгиевич© 2021 World Scientific Publishing Company.In this paper, we discuss the mechanism for generating the lepton/baryon number and its subsequent conservation based on extra-dimensional evolution. The internal angular momentum of extra space is related to the lepton/baryon charge. Extra space metric is assumed to be initially asymmetric. Symmetries appear during inflation due to an increase in entropy. Using the multidimensional field toy model, we show that internal angular momentum can accumulate in fermions, which could explain the lepton/baryon asymmetry of the universe.
- ПубликацияТолько метаданныеSelf-tuning inflation(2022) Petriakova, P.; Rubin, S. G.; Рубин, Сергей ГеоргиевичWe develop an inflationary model without small parameters on the basis of multidimensional f(R) gravity with a minimally coupled scalar field. The model is described by two stages of space expansion. The first one begins at energy scales about the D-dimensional Planck mass and ends with the de Sitter metric of our space and the maximally symmetric extra dimensions. In the following, the quantum fluctuations produce a wide set of inhomogeneous extra metrics in causally disconnected regions quickly generated in the de Sitter space. We find a specific extra space metric that leads to the effective Starobinsky model that fits the observational data. © 2022, The Author(s).
- ПубликацияТолько метаданныеCompact extra dimensions as the source of primordial black holes(2022) Nikulin, V. V.; Krasnov, M. A.; Rubin, S. G.; Никулин, Валерий Владимирович; Краснов, Максим Александрович; Рубин, Сергей ГеоргиевичThis article discusses a model of primordial black hole (PBH) formation at the reheating stage. These small/massive black holes appear due to the specific properties of the compact extra dimensions. The latter gives rise to the low energy model, containing an effective scalar field potential capable of domain wall production. Formed during inflation, these walls are quite dense, meaning they collapse soon after inflation ends. Discussion of the model is framed by the scope of multidimensional f ( R )-gravity. We study the possibility of the pure gravitational formation of primordial black holes (PBHs). Interpreting the scalar curvature of compact extra space R n as an effective scalar field in an Einstein framework and consider effective scalar-field theory that might potentially be capable of producing domain walls with a certain choice of parameters. Hence, we demonstrate that f ( R )-gravity contains a mechanism for PBH formation. The study assumed that cosmological inflation is an external process, which satisfied all the cosmological constraints on our mechanism.
- ПубликацияТолько метаданныеOn Mass Spectra of Primordial Black Holes(2021) Kirillov, A. A.; Rubin, S. G.; Кириллов, Александр Александрович; Рубин, Сергей ГеоргиевичCopyright © 2021 Kirillov and Rubin.Evidence for the primordial black holes (PBH) presence in the early Universe renews permanently. New limits on their mass spectrum challenge existing models of PBH formation. One of the known models is based on the closed walls collapse after the inflationary epoch. Its intrinsic feature is the multiple production of small mass PBH which might contradict observations in the nearest future. We show that the mechanism of walls collapse can be applied to produce substantially different PBH mass spectra if one takes into account the classical motion of scalar fields together with their quantum fluctuations at the inflationary stage. Analytical formulas have been developed that contain both quantum and classical contributions.
- ПубликацияТолько метаданныеFormation of Primordial Black Hole Clusters from Phase Transitions in the Early Universe(2019) Nikulin, V. V.; Rubin, S. G.; Kirillov, A. A.; Khromykh, L. A.; Никулин, Валерий Владимирович; Рубин, Сергей Георгиевич; Кириллов, Александр Александрович© 2019, Allerton Press, Inc. A new model of the formation of primordial black holes (PBHs) is considered. The PBH generation mechanism is based on the collapse of massive walls formed in a scalar field during second-order phase transitions caused by quantum fluctuations during inflation. An essential feature of the mechanism is the formation of primordial black holes in the form of clusters. An analytical spectrum of PBH masses is obtained. We also demonstrate the possibility of forming the clusters with a total mass of ∼ 10 5 –10 8 M ☉ , ∼ 1 pc in size, and ∼ 10 11 in number, which corresponds to the observational data on the number of galaxies in the visible region of the Universe. The prospect for the use of the proposed approach as a new scenario of the formation of galactic nuclei in the early Universe is shown.
- ПубликацияТолько метаданныеInflationary limits on the size of compact extra space(2019) Nikulin, V. V.; Rubin, S. G.; Никулин, Валерий Владимирович; Рубин, Сергей Георгиевич© 2019 World Scientific Publishing Company. We study restrictions imposed on the parameters of the Kaluza-Klein extra space supplied by the standard inflationary models. It is shown that the size of the extra space cannot be larger than ∼ 10-27cm and the D-dimensional Planck mass should be larger than ∼ 1013GeV. The validity of these estimates is discussed. We also study creation of stable excitations of scalar field as the result of the extra metric evolution.
- ПубликацияТолько метаданныеLocal Regions with Expanding Extra Dimensions(2021) Bronnikov, K. A.; Rubin, S. G.; Бронников, Кирилл Александрович; Рубин, Сергей ГеоргиевичIn this paper possible spatial domains, containing expanding extra dimensions, are studied. It is demonstrated that these domains are predicted in the framework of f(R) gravity (where R is the scalar curviture) and could appear due to quantum fluctuations during inflation. The interior of the domains is shown to be characterized by the multidimensional curvature ultimately tending to zero and a slowly growing size of the extra dimensions.
- ПубликацияТолько метаданныеUnveiling the early universe: Axion-like particles and their role in primordial structure formation(2024) Rubin, S. G.; Рубин, Сергей Георгиевич
- ПубликацияТолько метаданныеBlack Holes, Cosmology and Extra Dimensions(2021) Bronnikov, K. A.; Rubin, S. G.; Рубин, Сергей Георгиевич; Бронников, Кирилл АлександровичAssuming basic knowledge of special and general relativity, this book guides the reader to problems under consideration in modern research, concerning black holes, wormholes, cosmology, and extra dimensions. Its first part is devoted to local strong field configurations (black holes and wormholes) in general relativity and its most relevant extensions: scalar–tensor, f(R), and multidimensional theories. The second part discusses cosmology, including inflation and problems of a unified description of the whole evolution of the universe. The third part concerns multidimensional theories of gravity and contains a number of original results obtained by the authors. Expository work is conducted for a mechanism of symmetries and fundamental constants formation. The original approach to nonlinear multidimensional gravity that is able to construct a unique perspective describing different phenomena is highlighted. Much of the content was previously presented only in journal publications and is new for book contents, e.g., on regular black holes, various scalar field solutions, wormholes and their stability, inflation, clusters of primordial black holes, and multidimensional gravity. The last two topics are added in this new edition of the book. The other chapters are also updated to include new discoveries like the detection of gravitational waves.
- ПубликацияОткрытый доступBipolaron theory and its application in YBA2 CU3 O6+x(1997) Rubin, S. G.; Terekidi, A. G.; Рубин, Сергей Георгиевич