Kirill A. Bronnikov
Kirill A. Bronnikov
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Research Subjects
Kirill A. Bronnikov has a total of 184 co-authors. Here are the top co-authors by number of shared publications:
- Milena V. Skvortsova
RUDN University
37 shared publications - Sergei V. Bolokhov
RUDN University
34 shared publications - Sergey G. Rubin
National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)
20 shared publications - Julio Cesar Fabris
Universidade Federal do Espirito Santo
16 shared publications V. N. Melnikov
All-Russia Research Institute of Metrological Service (VNIIMS)
13 shared publications- Oleg B. Zaslavskii
Department of Physics and Technology, Kharkov V.N. Karazin National University, 4 Svoboda Square, Kharkov 61022, Ukraine
12 shared publications
Latest Publications
- Open Access
- 20 October 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (10) , 1190
Nonlinear electrodynamics and stability of spherically symmetric space-times in scalar-tensor gravity
We study linear perturbations of static, spherically symmetric solutions of scalar-tensor theories (STT) of gravity from the Bergmann-Wagoner-Nordtvedt class, sourced by nonlinear electrodynamics (NED). We obtain a general expression for the effective potential $$V_\textrm{eff}$$ governing the perturbation dynamics for theories with arbitrary scalar-electromagnetic interaction of the form $$L(\psi , F)$$ , where $$\psi $$ is a scalar field and $$F = F_{\mu \nu }F^{\mu \nu }$$ the electromagnetic invariant. This consideration includes, in particular, arbitrary scalar self-interaction potentials and scalar fields that can be phantom in some regions of space-time (the so-called trapped ghosts). Only radial (monopole) perturbations are considered here as the most likely ones to cause an instability. It is shown, in particular, that if NED has a correct Maxwell weak field limit, the zero charge limit of $$V_\textrm{eff}$$ does not contain any trace of NED, and the perturbation dynamics is the same as for vacuum STT solutions. The previously obtained stability results for STT-Maxwell solutions are shown to be extended without change to STT-NED solutions with equal electric and magnetic charges, implying $$F =0$$ . As an example of a solution with $$F\not \equiv 0$$ , we consider a system with a massless scalar and truncated Born-Infeld NED, both minimally coupled to gravity, in GR, and show that almost all results previously obtained for $$F=0$$ are qualitatively preserved.- 20 October 2026
- Published by Springer Nature in The European Physical Journal C
- Vol. 86 (10) , 1190
Open AccessNonlinear electrodynamics and stability of spherically symmetric space-times in scalar-tensor gravity
We study linear perturbations of static, spherically symmetric solutions of scalar-tensor theories (STT) of gravity from the Bergmann-Wagoner-Nordtvedt class, sourced by nonlinear electrodynamics (NED). We obtain a general expression for the effective potential $$V_\textrm{eff}$$ governing the perturbation dynamics for theories with arbitrary scalar-electromagnetic interaction of the form $$L(\psi , F)$$ , where $$\psi $$ is a scalar field and $$F = F_{\mu \nu }F^{\mu \nu }$$ the electromagnetic invariant. This consideration includes, in particular, arbitrary scalar self-interaction potentials and scalar fields that can be phantom in some regions of space-time (the so-called trapped ghosts). Only radial (monopole) perturbations are considered here as the most likely ones to cause an instability. It is shown, in particular, that if NED has a correct Maxwell weak field limit, the zero charge limit of $$V_\textrm{eff}$$ does not contain any trace of NED, and the perturbation dynamics is the same as for vacuum STT solutions. The previously obtained stability results for STT-Maxwell solutions are shown to be extended without change to STT-NED solutions with equal electric and magnetic charges, implying $$F =0$$ . As an example of a solution with $$F\not \equiv 0$$ , we consider a system with a massless scalar and truncated Born-Infeld NED, both minimally coupled to gravity, in GR, and show that almost all results previously obtained for $$F=0$$ are qualitatively preserved. - 24 August 2026
- Published by Pleiades Publishing Ltd in Gravitation and Cosmology
- Vol. 32 (3) , 376-382
On Gravitating Dyonic Configurations in Nonlinear Electrodynamics
We consider static, spherically symmetric configurations of nonlinear electromagnetic fields with Lagrangians \(L(f)\), where \(f=F_{\mu\nu}F^{\mu\nu}\), in general relativity (GR) and other metric theories of gravity. The corresponding exact solutions are well known in the framework of GR in cases where only an electric charge (\(q_{e}\)) or a magnetic charge (\(q_{m}\)) are present, but only a few solutions in particular examples of \(L(f)\) are known for dyonic systems with both nonzero \(q_{e}\) and \(q_{m}\). We study the properties of such systems in the special case of equal electric and magnetic charges and, assuming a correct Maxwell limit of \(L(f)\), show that there always exists such a configuration of the electromagnetic field that the invariant \(f\) is zero in the whole space. It leads to the existence of the corresponding families of solutions both in GR in the presence of other sources of gravity (like fluids or scalar fields) and in a wide range of extended theories of gravity (e.g., scalar-tensor and \(f(R)\) gravity), in which the nonlinear electromagnetic field behaves in an especially simple manner.- 24 August 2026
- Published by Pleiades Publishing Ltd in Gravitation and Cosmology
- Vol. 32 (3) , 376-382
On Gravitating Dyonic Configurations in Nonlinear Electrodynamics
We consider static, spherically symmetric configurations of nonlinear electromagnetic fields with Lagrangians \(L(f)\), where \(f=F_{\mu\nu}F^{\mu\nu}\), in general relativity (GR) and other metric theories of gravity. The corresponding exact solutions are well known in the framework of GR in cases where only an electric charge (\(q_{e}\)) or a magnetic charge (\(q_{m}\)) are present, but only a few solutions in particular examples of \(L(f)\) are known for dyonic systems with both nonzero \(q_{e}\) and \(q_{m}\). We study the properties of such systems in the special case of equal electric and magnetic charges and, assuming a correct Maxwell limit of \(L(f)\), show that there always exists such a configuration of the electromagnetic field that the invariant \(f\) is zero in the whole space. It leads to the existence of the corresponding families of solutions both in GR in the presence of other sources of gravity (like fluids or scalar fields) and in a wide range of extended theories of gravity (e.g., scalar-tensor and \(f(R)\) gravity), in which the nonlinear electromagnetic field behaves in an especially simple manner.- 2 July 2026
- Published by Springer Nature
- p. 387-400
Alexei Starobinsky and Wormhole Physics
- Open Access
- 12 March 2026
- Published by Scilight Press Pty Ltd in International Journal of Gravitation and Theoretical Physics
- Vol. 2 (1) , 2
Stability Ranges of Magnetic Black Holes and Mirror (Topological) Stars in 5D Gravity
We discuss static, spherically symmetric solutions to the 5D Einstein- Maxwell equations (belonging to wide classes of multidimensional solutions known at least from the 1990s) and select among them those which must observationally look like local objects whose surface reflects back particles or signals getting there, the so-called mirror stars (also called “topological stars” by some authors). Their significant parameters are the Schwarzschild mass m and the magnetic charge q, such that q2 > 3m2 , while the radius of their mirror surface is rb = 2q2 /(3m) > 2m. We also discuss their black hole counterparts for which q2 ≤ 3m2 . For both these objects, we study spherically symmetric time-dependent perturbations and determine the stability regions in their parameter spaces. Thus, mirror stars turn out to be stable only at rb < rb(crit) ≈ 4.004m, while the black holes prove to be stable in the whole range of their parameters. We calculate the fundamental frequencies and decay rates of black hole perturbations using the WKB and time domain methods. Our stability results disagree with some of those previously announced in the literature.
- 12 March 2026
- Published by Scilight Press Pty Ltd in International Journal of Gravitation and Theoretical Physics
- Vol. 2 (1) , 2
Open AccessStability Ranges of Magnetic Black Holes and Mirror (Topological) Stars in 5D Gravity
We discuss static, spherically symmetric solutions to the 5D Einstein- Maxwell equations (belonging to wide classes of multidimensional solutions known at least from the 1990s) and select among them those which must observationally look like local objects whose surface reflects back particles or signals getting there, the so-called mirror stars (also called “topological stars” by some authors). Their significant parameters are the Schwarzschild mass m and the magnetic charge q, such that q2 > 3m2 , while the radius of their mirror surface is rb = 2q2 /(3m) > 2m. We also discuss their black hole counterparts for which q2 ≤ 3m2 . For both these objects, we study spherically symmetric time-dependent perturbations and determine the stability regions in their parameter spaces. Thus, mirror stars turn out to be stable only at rb < rb(crit) ≈ 4.004m, while the black holes prove to be stable in the whole range of their parameters. We calculate the fundamental frequencies and decay rates of black hole perturbations using the WKB and time domain methods. Our stability results disagree with some of those previously announced in the literature.
- 21 November 2025
- Published by World Scientific Pub Co Pte Ltd in International Journal of Modern Physics D
- Vol. 35 (02)
Formation and evolution of a 2-brane structure in multidimensional f(R) gravity
It has been previously shown that multidimensional [ ] gravity can lead to a two-brane structure. In this paper, we analyze such a model with a spatially flat 4D de Sitter (dS) cosmology whose Hubble parameter H determines the universal energy scale. We show that the two-brane metric is nucleated at the highest energies. The distance between the branes grows gradually as the energy decreases, tending to a finite value at zero energy density. It is stated that the physical parameters such as the 4D Planck mass, the Higgs vacuum expectation value, and vacuum energy density vary with the evolving universal energy scale, even on the classical level. We also show that the Higgs vacuum expectation value is different on different branes.
- 21 November 2025
- Published by World Scientific Pub Co Pte Ltd in International Journal of Modern Physics D
- Vol. 35 (02)
Formation and evolution of a 2-brane structure in multidimensional f(R) gravity
It has been previously shown that multidimensional [ ] gravity can lead to a two-brane structure. In this paper, we analyze such a model with a spatially flat 4D de Sitter (dS) cosmology whose Hubble parameter H determines the universal energy scale. We show that the two-brane metric is nucleated at the highest energies. The distance between the branes grows gradually as the energy decreases, tending to a finite value at zero energy density. It is stated that the physical parameters such as the 4D Planck mass, the Higgs vacuum expectation value, and vacuum energy density vary with the evolving universal energy scale, even on the classical level. We also show that the Higgs vacuum expectation value is different on different branes.
- Open Access
Gravitational Lensing by Lemaître–Tolman–Bondi Wormholes in a Friedmann Universe
The Lemaître–Tolman–Bondi (LTB) solution to the Einstein equations describes the dynamics of a self-gravitating spherically symmetric dust cloud with an arbitrary density profile and any distribution of initial velocities, encoded in three arbitrary functions , , and , where R is a radial coordinate in the comoving reference frame. A particular choice of these functions corresponds to a wormhole geometry with a throat defined as a sphere of minimum radius at a fixed time instant. In this paper we explore LTB wormholes and discuss their possible observable appearance, studying in detail the effects of gravitational lensing by such objects. For this aim, we study photon motion in wormhole space-time inscribed in a closed Friedmann dust-filled universe and find the wormhole shadow as it could be seen by a distant observer. Because the LTB wormhole is a dynamic object, we analyze the dependence of its shadow size on the observation time and on the initial size of the wormhole region. We reveal that the angular size of the shadow exhibits a non-monotonic dependence on the observation time. At early times, the shadow size decreases as photons with smaller angular momentum gradually reach the observer. At later times, the expansion of the Friedmann universe becomes a dominant factor that leads to an increase in the shadow size.Open AccessGravitational Lensing by Lemaître–Tolman–Bondi Wormholes in a Friedmann Universe
The Lemaître–Tolman–Bondi (LTB) solution to the Einstein equations describes the dynamics of a self-gravitating spherically symmetric dust cloud with an arbitrary density profile and any distribution of initial velocities, encoded in three arbitrary functions , , and , where R is a radial coordinate in the comoving reference frame. A particular choice of these functions corresponds to a wormhole geometry with a throat defined as a sphere of minimum radius at a fixed time instant. In this paper we explore LTB wormholes and discuss their possible observable appearance, studying in detail the effects of gravitational lensing by such objects. For this aim, we study photon motion in wormhole space-time inscribed in a closed Friedmann dust-filled universe and find the wormhole shadow as it could be seen by a distant observer. Because the LTB wormhole is a dynamic object, we analyze the dependence of its shadow size on the observation time and on the initial size of the wormhole region. We reveal that the angular size of the shadow exhibits a non-monotonic dependence on the observation time. At early times, the shadow size decreases as photons with smaller angular momentum gradually reach the observer. At later times, the expansion of the Friedmann universe becomes a dominant factor that leads to an increase in the shadow size. - Open AccessFormation and evolution of a 2-brane structure in multidimensional $f(R)$ gravityIt has been previously shown that multidimensional $f(R)$ gravity {can lead} to a two-brane structure. In this paper, we analyze such a model with a spatially flat 4D de Sitter (dS) cosmology {whose Hubble parameter $H$ determines the universal energy scale}. We show that the two-brane metric is nucleated at the highest energies. The distance between the branes grows gradually as the energy decreases, tending to a finite value at zero energy density. It is stated that the physical parameters such as the 4D Planck mass, the Higgs vacuum expectation value, and vacuum energy density vary with the evolving universal energy scale, even on the classical level. We also show that the Higgs vacuum expectation value is different on different branes.Open AccessFormation and evolution of a 2-brane structure in multidimensional $f(R)$ gravityIt has been previously shown that multidimensional $f(R)$ gravity {can lead} to a two-brane structure. In this paper, we analyze such a model with a spatially flat 4D de Sitter (dS) cosmology {whose Hubble parameter $H$ determines the universal energy scale}. We show that the two-brane metric is nucleated at the highest energies. The distance between the branes grows gradually as the energy decreases, tending to a finite value at zero energy density. It is stated that the physical parameters such as the 4D Planck mass, the Higgs vacuum expectation value, and vacuum energy density vary with the evolving universal energy scale, even on the classical level. We also show that the Higgs vacuum expectation value is different on different branes.
- Open Access
- 25 September 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (9) , 1-11
On the stability of exceptional Brans–Dicke wormholes
In our previous papers we have analyzed the stability of vacuum and electrovacuum static, spherically symmetric space-times in the framework of the Bergmann–Wagoner–Nordtvedt class of scalar-tensor theories (STT) of gravity. In the present paper, we continue this study by examining the stability of exceptional solutions of the Brans–Dicke theory with the coupling constant $$\omega =0$$ that were not covered in the previous studies. Such solutions describe neutral or charged wormholes and involve a conformal continuation: the standard conformal transformation maps the whole Einstein-frame manifold $${\mathbb {M}}_\textrm{E}$$ to only a part of the Jordan-frame manifold $${\mathbb {M}}_\textrm{J}$$ , which has to be continued beyond the emerging regular boundary S, and the new region maps to another manifold $${\mathbb {M}}_\textrm{E}$$ $${}_{-}$$ . The metric in $${\mathbb {M}}_\textrm{J}$$ is symmetric with respect to S only if the charge q is zero. Our stability study concerns radial (monopole) perturbations, and it is shown that the wormhole is stable if $$q \ne 0$$ and unstable only in the symmetric case $$q=0$$ .- 25 September 2025
- Published by Springer Nature in The European Physical Journal C
- Vol. 85 (9) , 1-11
Open AccessOn the stability of exceptional Brans–Dicke wormholes
In our previous papers we have analyzed the stability of vacuum and electrovacuum static, spherically symmetric space-times in the framework of the Bergmann–Wagoner–Nordtvedt class of scalar-tensor theories (STT) of gravity. In the present paper, we continue this study by examining the stability of exceptional solutions of the Brans–Dicke theory with the coupling constant $$\omega =0$$ that were not covered in the previous studies. Such solutions describe neutral or charged wormholes and involve a conformal continuation: the standard conformal transformation maps the whole Einstein-frame manifold $${\mathbb {M}}_\textrm{E}$$ to only a part of the Jordan-frame manifold $${\mathbb {M}}_\textrm{J}$$ , which has to be continued beyond the emerging regular boundary S, and the new region maps to another manifold $${\mathbb {M}}_\textrm{E}$$ $${}_{-}$$ . The metric in $${\mathbb {M}}_\textrm{J}$$ is symmetric with respect to S only if the charge q is zero. Our stability study concerns radial (monopole) perturbations, and it is shown that the wormhole is stable if $$q \ne 0$$ and unstable only in the symmetric case $$q=0$$ . - Open Access
Gravitational lensing by Lemaître-Tolman-Bondi wormholes in a Friedmann universe
The Lemaître-Tolman-Bondi (LTB) solution to the Einstein equations describes the dynamics of a self-gravitating spherically symmetric dust cloud with an arbitrary density profile and any distribution of initial velocities, encoded in three arbitrary functions $f(R)$, $F(R)$, and $τ_0(R)$, where $R$ is a radial coordinate in the comoving reference frame. A particular choice of these functions corresponds to a wormhole geometry with a throat defined as a sphere of minimum radius at a fixed time instant. In this paper we explore LTB wormholes and discuss their possible observable appearance studying in detail the effects of gravitational lensing by such objects. For this aim, we study photon motion in wormhole space-time inscribed in a closed Friedmann dustfilled universe and find the wormhole shadow as it could be seen by a distant observer. Since the LTB wormhole is a dynamic object, we analyze the dependence of its shadow size on the observation time and on the initial size of the wormhole region. We reveal that the angular size of the shadow exhibits a non-monotonic dependence on the observation time. At early times, the shadow size decreases as photons with smaller angular momentum gradually reach the observer. At later times, the expansion of the Friedmann Universe becomes a dominant factor that leads to an increase in the shadow size.Open AccessGravitational lensing by Lemaître-Tolman-Bondi wormholes in a Friedmann universe
The Lemaître-Tolman-Bondi (LTB) solution to the Einstein equations describes the dynamics of a self-gravitating spherically symmetric dust cloud with an arbitrary density profile and any distribution of initial velocities, encoded in three arbitrary functions $f(R)$, $F(R)$, and $τ_0(R)$, where $R$ is a radial coordinate in the comoving reference frame. A particular choice of these functions corresponds to a wormhole geometry with a throat defined as a sphere of minimum radius at a fixed time instant. In this paper we explore LTB wormholes and discuss their possible observable appearance studying in detail the effects of gravitational lensing by such objects. For this aim, we study photon motion in wormhole space-time inscribed in a closed Friedmann dustfilled universe and find the wormhole shadow as it could be seen by a distant observer. Since the LTB wormhole is a dynamic object, we analyze the dependence of its shadow size on the observation time and on the initial size of the wormhole region. We reveal that the angular size of the shadow exhibits a non-monotonic dependence on the observation time. At early times, the shadow size decreases as photons with smaller angular momentum gradually reach the observer. At later times, the expansion of the Friedmann Universe becomes a dominant factor that leads to an increase in the shadow size. - Open Access
On the stability of exceptional Brans-Dicke wormholes
In our previous papers we have analyzed the stability of vacuum and electrovacuum static, spherically symmetric space-times in the framework of the Bergmann-Wagoner-Nordtvedt class of scalar-tensor theories (STT) of gravity. In the present paper, we continue this study by examining the stability of exceptional solutions of the Brans-Dicke theory with the coupling constant $ω=0$ that were not covered in the previous studies. Such solutions describe neutral or charged wormholes and involve a conformal continuation: the standard conformal transformation maps the whole Einstein-frame manifold ${\mathbb M}_E$ to only a part of the Jordan-frame manifold ${\mathbb M}_J$, which has to be continued beyond the emerging regular boundary S, and the new region maps to another manifold ${\mathbb M}_{E-}$. The metric in ${\mathbb M}_J$ is symmetric with respect to S only if the charge $q$ is zero. Our stability study concerns radial (monopole) perturbations, and it is shown that the wormhole is stable if $q \ne 0$ and unstable only in the symmetric case $q=0$Open AccessOn the stability of exceptional Brans-Dicke wormholes
In our previous papers we have analyzed the stability of vacuum and electrovacuum static, spherically symmetric space-times in the framework of the Bergmann-Wagoner-Nordtvedt class of scalar-tensor theories (STT) of gravity. In the present paper, we continue this study by examining the stability of exceptional solutions of the Brans-Dicke theory with the coupling constant $ω=0$ that were not covered in the previous studies. Such solutions describe neutral or charged wormholes and involve a conformal continuation: the standard conformal transformation maps the whole Einstein-frame manifold ${\mathbb M}_E$ to only a part of the Jordan-frame manifold ${\mathbb M}_J$, which has to be continued beyond the emerging regular boundary S, and the new region maps to another manifold ${\mathbb M}_{E-}$. The metric in ${\mathbb M}_J$ is symmetric with respect to S only if the charge $q$ is zero. Our stability study concerns radial (monopole) perturbations, and it is shown that the wormhole is stable if $q \ne 0$ and unstable only in the symmetric case $q=0$