Article
Astronomy & Astrophysics
M. S. Churilova, R. A. Konoplya, Z. Stuchlik, A. Zhidenko
Summary: Analytical solutions for traversable asymptotically flat and symmetric wormholes have been obtained independently in two different theories, without the need for exotic matter. Additionally, a numerically obtained smooth normalizable asymmetric wormhole solution has been achieved in one of the theories. The study focuses on the quasinormal ringing of these wormholes, particularly in mimicking near extremal Reissner-Nordstrom black holes, and calculates the radius of shadows cast by the wormholes.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Alexandre M. R. Almeida, Julio C. Fabris, Mahamadou Hamani Daouda, Richard Kerner, Hermano Velten, Willian S. Hipolito-Ricaldi
Summary: This paper introduces a unimodular version of the Brans-Dicke theory with a constrained Lagrangian formulation, resulting in traceless field equations. The vacuum solutions in the cosmological background reproduce the solutions of the usual Brans-Dicke theory with an additional cosmological constant term. A perturbative analysis of the scalar modes reveals both stable and unstable configurations, contrasting with the Brans-Dicke case where only stable configurations occur. However, the tensorial modes remain unchanged in this theory compared to the traditional Brans-Dicke theory.
Article
Astronomy & Astrophysics
Kunio Kaneta, Kin-ya Oda, Motohiko Yoshimura
Summary: This paper presents a cosmological analysis of extended Jordan-Brans-Dicke (eJBD) gravity in the Einstein metric frame. It is the first systematic investigation of how to introduce the lagrangian of standard particle physics in the eJBD framework consistently. The study is significant for understanding the time evolution of eJBD gravity and its compatibility with observational and laboratory bounds.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Physics, Multidisciplinary
S. K. Maurya, Ksh Newton Singh, Saibal Ray
Summary: This study applies the Brans-Dicke theory of gravitation as an alternative to general relativity for modeling anisotropic compact stellar objects. By considering specific conditions for the space-time, the field equations become solvable and the numerical solution for the Brans-Dicke scalar field phi fits well with a known function. The solutions set appears viable based on observational data.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Astronomy & Astrophysics
Bardia H. Fahim, Valerio Faraoni, Andrea Giusti
Summary: A new one-parameter family of solutions to the vacuum Brans-Dicke field equations is reported in this study, which are spherically symmetric, inhomogeneous, and time-dependent. These solutions are conformal to the Roberts scalar field geometries of Einstein gravity and contain a naked central singularity. By using this new solution as a seed, another two-parameter family of solutions can be generated through a known symmetry of vacuum Brans-Dicke gravity.
Article
Physics, Particles & Fields
M. Dehghani
Summary: It has been shown that the exact solutions of the 4D Brans-Dicke-Maxwell (BDM) theory are Reissner-Nordstrom (RN) black holes coupled to a constant scalar field or zero. However, when the scalar potential is not constant or zero, novel black hole solutions affected by a nontrivial scalar hair are obtained. The inclusion of the scalar hair makes the asymptotic behavior of the solutions non-flat and non-AdS, and the theory allows for the occurrence of multi-horizon black holes due to the conformal invariance of Maxwell's electrodynamics, implying anti-evaporation quantum effect. The thermodynamic properties and stability of the BDM black holes are analyzed and found to satisfy the first law of black hole thermodynamics.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Multidisciplinary
Ashutosh Singh
Summary: This article explores the non-equilibrium thermodynamic aspects of cosmological apparent horizon in Brans-Dicke gravity, studying the time evolution of total entropy, entropy production, and entropy of matter inside the horizon. The validity of the generalized second law of thermodynamics in expanding and bouncing Brans-Dicke cosmologies is also examined.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Physics, Particles & Fields
Hatice Ozer, Ozgur Delice
Summary: The study investigates weak field gravitational wave solutions in Brans-Dicke theory with a cosmological constant, revealing massless scalar waves and their effects on free particles and polarization properties. The analysis also includes the role of the cosmological constant in these phenomena and discusses the energy flux of these waves, leading to an extension of the Cosmic no Hair Conjecture to BD theory with a cosmological constant.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
S. Ghaffari, Giuseppe Gaetano Luciano, S. Capozziello
Summary: We constructed a holographic model for dark energy in the Brans-Dicke cosmology by incorporating the Barrow entropy. The Hubble horizon was used as the IR cutoff to explore the cosmological consequences. We found that both the non-interacting and interacting cases can explain the current accelerated expansion of the universe, unlike the standard holographic dark energy model. Stability analysis showed that the non-interacting model was unstable, while the sign-changeable interacting model was stable only for certain parameter values. The linear interacting model always predicted a stable universe. The consistency of the model with cosmological observations was discussed.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Physics, Mathematical
Nisha Godani
Summary: This study focuses on traversable wormholes using three different gravity models. The research explores wormhole solutions, defining a shape function and examining stability and energy conditions for each model.
INTERNATIONAL JOURNAL OF GEOMETRIC METHODS IN MODERN PHYSICS
(2021)
Article
Astronomy & Astrophysics
Grigoris Panotopoulos, Angel Rincon, Ilidio Lopes
Summary: This study focuses on the X-ray emission of low-mass black hole binaries in massive Brans-Dicke gravity. The accretion disk is computed using the Shakura-Sunyaev model, assuming the gravitational field generated by the stellar-mass black hole is analogous to the Schwarzschild space-time of Einstein's theory in massive Brans-Dicke gravity. The study investigates the effects of the mass of the scalar field on the properties of the binary.
Article
Astronomy & Astrophysics
Tong Jiang, Ning Dai, Yungui Gong, Dicong Liang, Chao Zhang
Summary: Intermediate/Extreme mass ratio inspiral (I/EMRI) system is an important tool to test the nature of gravity in strong field. By computing orbital evolutions and generating waveform templates, we constrain the parameters of Brans-Dicke theory.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Gabriele S. J. Gionti
Summary: This study explores the Jordan and Einstein frames in the context of Hamiltonian formalism, analyzing the Brans-Dicke theory using Dirac's constraint theory. Contrary to popular belief, the Weyl transformation between these frames is not considered a canonical transformation in the Hamiltonian formalism, highlighting quantum mechanical inequivalence. Additionally, a canonical transformation is demonstrated in the study.
Article
Astronomy & Astrophysics
Matteo Galaverni, Gabriele Gionti
Summary: This article presents a Hamiltonian Dirac's constraint analysis of the omega = -3/2 Brans-Dicke theory, including the Gibbons-Hawking-York boundary term. It derives the Hamiltonian Dirac's constraints and constraint algebra in both the Jordan and the Einstein frames, and demonstrates that the constraint algebra in these frames is not equivalent.
Article
Astronomy & Astrophysics
Tan Liu, Yan Wang, Wen Zhao
Summary: In modified gravity theories, the waveforms used to study standard sirens should be modified. The modifications involve wave-generation effects and wave-propagation effects. Previous waveform studies mainly focused on wave-propagation effects, neglecting wave-generation effects. In this work, we construct consistent waveforms for standard sirens in the Brans-Dicke theory, including both wave-generation and wave-propagation effects. The analysis shows that ignoring wave-generation effects can lead to parameter estimation biases.
Article
Physics, Particles & Fields
Ernesto F. Eiroa, Emilio Rubin de Celis, Claudio Simeone
EUROPEAN PHYSICAL JOURNAL C
(2016)
Article
Physics, Particles & Fields
Ernesto F. Eiroa, Griselda Figueroa Aguirre
EUROPEAN PHYSICAL JOURNAL C
(2016)
Article
Physics, Particles & Fields
Javier Badia, Ernesto F. Eiroa
EUROPEAN PHYSICAL JOURNAL C
(2017)
Article
Physics, Particles & Fields
Ernesto F. Eiroa, Griselda Figueroa Aguirre
EUROPEAN PHYSICAL JOURNAL C
(2018)
Article
Physics, Particles & Fields
Ernesto F. Eiroa, Carlos M. Sendra
EUROPEAN PHYSICAL JOURNAL C
(2018)
Article
Physics, Particles & Fields
Fabrizio Canfora, Ernesto F. Eiroa, Carlos M. Sendra
EUROPEAN PHYSICAL JOURNAL C
(2018)
Article
Physics, Particles & Fields
Ernesto F. Eiroa, Griselda Figueroa Aguirre
EUROPEAN PHYSICAL JOURNAL C
(2019)
Article
Physics, Particles & Fields
Ernesto F. Eiroa, Emilio Rubin de Celis, Claudio Simeone
EUROPEAN PHYSICAL JOURNAL C
(2019)
Article
Physics, Multidisciplinary
Iarley P. Lobo, Martin G. Richarte, J. P. Morais Graca, H. Moradpour
EUROPEAN PHYSICAL JOURNAL PLUS
(2020)
Article
Physics, Multidisciplinary
Ernesto F. Eiroa, Griselda Figueroa Aguirre
EUROPEAN PHYSICAL JOURNAL PLUS
(2020)
Article
Astronomy & Astrophysics
Martin G. Richarte, Ebano L. Martins, Julio C. Fabris
Summary: This study revisits the absorption and scattering process of a massless scalar field interacting with a charged-dilatonic black hole. The study finds that the amplitude of the dilatonic black hole is lower than the Reissner-Nordstrom one for mild frequencies. It also shows that smaller values of M omega lead to more significant amplitudes in the differential scattering cross section.
Article
Astronomy & Astrophysics
Julio C. Fabris, Martin G. Richarte, Alberto Saa
Summary: This study revisits the analytical continuation method used to compute quasinormal modes and frequencies of a potential barrier V. In an exactly soluble problem, though the associated Schrodinger operator lacks self-adjointness, it still has self-adjoint extensions. However, the eigenstates corresponding to the analytically continued QNM do not belong to any self-adjoint extension domain.
Article
Astronomy & Astrophysics
Javier Badia, Ernesto F. Eiroa
Article
Astronomy & Astrophysics
Ernesto F. Eiroa, Griselda Figueroa Aguirre, Jose M. M. Senovilla
Article
Astronomy & Astrophysics
Ernesto F. Eiroa, Griselda Figueroa Aguirre
Article
Physics, Multidisciplinary
Tinggui Chen, Baizhan Xia, Dejie Yu, Chuanxing Bi
Summary: This study proposes a gradient phononic crystal structure for enhanced acoustic sensing. By breaking the symmetry of the PC structure, topologically protected edge states are introduced, resulting in topological acoustic rainbow trapping. The robustness and enhancement properties are verified numerically and experimentally.
