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Бронников, Кирилл Александрович

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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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Бронников

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Кирилл Александрович

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Теперь показываю 1 - 10 из 37

Только метаданные
Regular black holes as an alternative to black bounce
(2024) Bronnikov, K. A.; Бронников, Кирилл Александрович
Только метаданные
On the stability of electrovacuum space-times in scalar–tensor gravity
(2024) Bronnikov, K. A.; Bolokhov, S. V.; Skvortsova, M. V.; Ibadov, R.; Бронников, Кирилл Александрович
Только метаданные
A Regular Center Instead of a Black Bounce
(2024) Bolokhov, S. V.; Bronnikov, K. A.; Skvortsova, M. V.; Бронников, Кирилл Александрович
Только метаданные
Local Regions with Expanding Extra Dimensions
(2021) Bronnikov, K. A.; Rubin, S. G.; Бронников, Кирилл Александрович; Рубин, Сергей Георгиевич
In 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.
Только метаданные
2nd Comment on "On the Klein–Gordon oscillator in topologically charged Ellis–Bronnikov type wormhole spacetime"
(2024) Bronnikov, K. A.; Бронников, Кирилл Александрович
Только метаданные
On black bounce space-times in non-linear electrodynamics
(2024) Alencar, G.; Bronnikov, K. A.; Rodrigues, M. E.; Gómez, D. S. -C.; Бронников, Кирилл Александрович
Открытый доступ
Regular Black Holes Sourced by Nonlinear Electrodynamics
(Springer, 2023) Бронников, К. А.; Бронников, Кирилл Александрович
This chapter is a brief review on the existence and basic properties of static, spherically symmetric regular black hole solutions of general relativity where the source of gravity is represented by nonlinear electromagnetic fields with the Lagrangian function L depending on the single invariant $$f = F_{\mu \nu }F^{\mu \nu }$$ or on two variables: either L(f, h), where $$h = {}^*\!F_{\mu \nu }F^{\mu \nu }$$ , where $${}^*\!F_{\mu \nu }$$ is the Hodge dual of $$F_{\mu \nu }$$ , or L(f, J), where $$J = F_{\mu \nu }F^{\nu \rho } F_{\rho \sigma } F^{\sigma \mu }$$ . A number of no-go theorems are discussed, revealing the conditions under which the space-time cannot have a regular center, among which the theorems concerning L(f, J) theories are probably new. These results concern both regular black holes and regular particlelike or starlike objects (solitons) without horizons. Thus, a regular center in solutions with an electric charge $$q_e\ne 0$$ is only possible with nonlinear electrodynamics (NED) having no Maxwell weak field limit. Regular solutions with L(f) and L(f, J) NED, possessing a correct (Maxwell) weak-field limit, are possible if the system contains only a magnetic charge $$q_m \ne 0$$ . It is shown, however, that in such solutions the causality and unitarity as well as dynamic stability conditions are inevitably violated in a neighborhood of the center. Some particular examples are discussed.
Открытый доступ
Inhomogeneous compact extra dimensions and de Sitter cosmology
(2020) Popov, A. A.; Bronnikov, K. A.; Rubin, S. G.; Бронников, Кирилл Александрович; Рубин, Сергей Георгиевич
© 2020, The Author(s).In the framework of multidimensional f(R) gravity, we study the possible metrics of compact extra dimensions assuming that our 4D space has the de Sitter metric. Manifolds described by such metrics could be formed at the inflationary and even higher energy scales. It is shown that in the presence of a scalar field, it is possible to obtain a variety of inhomogeneous metrics in the extra factor space M2. Each of these metrics leads to a certain value of the 4D cosmological constant Λ4, and in particular, it is possible to obtain Λ4= 0 , as is confirmed by numerically obtained solutions. A nontrivial scalar field distribution in the extra dimensions is an important feature of this family of metrics. The obtained solutions are shown to be stable under extra-dimensional perturbations.
Открытый доступ
Hybrid Metric-Palatini Gravity: Regular Stringlike Configurations
(2020) Bronnikov, K.; Bolokhov, S.; Skvortsova, M.; Бронников, Кирилл Александрович
We discuss static, cylindrically symmetric vacuum solutions of hybrid metric-Palatini gravity (HMPG), a recently proposed theory that has been shown to successfully pass the local observational tests and produce a certain progress in cosmology. We use HMPG in its well-known scalar-tensor representation. The latter coincides with general relativity containing, as a source of gravity, a conformally coupled scalar field phi and a self-interaction potential V(phi). The phi field can be canonical or phantom, and, accordingly, the theory splits into canonical and phantom sectors. We seek solitonic (stringlike) vacuum solutions of HMPG, that is, completely regular solutions with Minkowski metric far from the symmetry axis, with a possible angular deficit. A transition of the theory to the Einstein conformal frame is used as a tool, and many of the results apply to the general Bergmann-Wagoner-Nordtvedt class of scalar-tensor theories as well as f(R) theories of gravity. One of these results is a one-to-one correspondence between stringlike solutions in the Einstein and Jordan frames if the conformal factor that connects them is everywhere regular. An algorithm for the construction of stringlike solutions in HMPG and scalar-tensor theories is suggested, and some examples of such solutions are obtained and discussed.
Открытый доступ
Cylindrical systems in general relativity
(2020) Santos, N. O.; Wang, A.; Bronnikov, K. A.; Бронников, Кирилл Александрович
© 2020 IOP Publishing Ltd.With the arrival of the era of gravitational wave astronomy, the strong gravitational field regime will be explored soon in various aspects. In this article, we provide a general review over cylindrical systems in Einstein's theory of general relativity. In particular, we first review the general properties, both local and global, of several important solutions of Einstein's field equations, including the Levi-Civita and Lewis solutions and their extensions to include the cosmological constant and matter fields, and pay particular attention to properties that represent the generic features of the theory, such as the formation of the observed extragalactic jets and gravitational Faraday rotation. We also review studies of cylindrical wormholes, gravitational collapse and hoop conjecture, and polarizations of gravitational waves. In addition, by rigorously defining cylindrically symmetric spacetimes, we clarify various (incorrect) claims existing in the literature, regarding to the generality of such spacetimes.