Article
Physics, Particles & Fields
R. Chan, M. F. A. da Silva, V. H. Satheeshkumar
Summary: The text analyzes all possible spherically symmetric exterior vacuum solutions allowed by the Einstein-Aether theory with static aether. Three classes of solutions are identified based on different values of a combination of free parameters, with explicit analytical solutions provided for specific cases. There are singularities present in some solutions while others are asymptotically flat spacetimes without horizons. This characteristic is different from general relativity. Additionally, the thermodynamics for the case where a horizon exists is briefly discussed.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Jacob Oost, Shinji Mukohyama, Anzhong Wang
Summary: In Einstein-aether theory, spherically symmetric spacetimes are studied in different coordinate systems, yielding exact vacuum solutions characterized by parameters. These solutions satisfy observational constraints, but possess singularities leading to spacetime becoming singular.
Article
Physics, Multidisciplinary
Farook Rahaman, Nayan Sarkar
Summary: This paper discusses the systematics and phase transitions in the early universe, and the resulting topological defects. By analyzing these defects, the spacetime geometry outside of a spherically symmetric distribution of matter is obtained, ultimately leading to a solution that describes a black hole.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yanni Zhu, Towe Wang
Summary: In this study, an analytical solution in Einstein-aether theory was explicitly presented and compared with the previously known static aether solution. By investigating the photon sphere and shadow of the solution with varying coupling constants, the results were compared with those of the Schwarzschild black hole.
Article
Physics, Particles & Fields
Bruno J. Barros, Zahra Haghani, Tiberiu Harko, Francisco S. N. Lobo
Summary: This study explores interior static and spherically symmetric solutions in a gravity theory with a Lagrangian constructed from a three-form field A(alpha beta gamma), revealing that three-form field stars may have greater mass. A comparison between three-form gravity theory and general relativity indicates differences in their description of astrophysical phenomena.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
R. Chan, M. F. A. da Silva
Summary: The work presents all possible solutions for a static cylindrical symmetric spacetime in the Einstein-Aether theory, including a generalization of the Levi-Civita spacetime in General Relativity. The study shows that the geodesic properties of the generalized LC solution in EA theory depend on the parameter c(14) of the aether field, with radial and z-direction geodesics being allowed only for certain values of sigma and c(14). The spacetime exhibits unusual properties compared to General Relativity, such as restrictions on z-direction geodesics and a non-singular region for sigma > 1/2.
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2021)
Article
Astronomy & Astrophysics
A. Savas Arapoglu, Sermet Cagan, A. Emrah Yukselci
Summary: We numerically examine the exterior solution of spherically symmetric and static configuration in scalar-tensor theories using the nonminimally coupled scalar field. Our main purpose is to find approximate analytical expressions that are weakly dependent on the model parameters to fit the numerical solutions in the interested region.
Article
Physics, Particles & Fields
M. O. Katanaev
Summary: A general analytic spherically symmetric solution of the Bogomol'nyi equations has been discovered, depending on two constants and an arbitrary function on radius. This solution includes the Bogomol'nyi-Prasad-Sommerfield and Singleton solutions as specific cases, leading to the derivation of all spherically symmetric 't Hooft-Polyakov monopoles with massless scalar field and minimal energy.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Cecilia Nagy, Zoltan Keresztes, Laszlo A. Gergely
Summary: The study explores black hole solutions of Horndeski scalar-tensor theory using a nonorthogonal double foliation. It proves the compatibility of Horndeski Lagrangians with observations in an effective field theory approach. New solutions with intriguing logarithmic singularities and asymptotically nonflat behavior are derived, evading previous uniqueness theorems.
Article
Astronomy & Astrophysics
Wenyi Wang, Hua Chen, Taishi Katsuragawa
Summary: This study analyzes the theoretical solutions of f(Q) gravity, revealing restrictions on its functional form and studying the properties of Schwarzschild-like solutions in nontrivial f(Q) gravity.
Article
Astronomy & Astrophysics
Vittorio De Falco, Mariafelicia De Laurentis, Salvatore Capozziello
Summary: The study focuses on measuring the epicyclic frequencies to infer information on a given self-gravitating system and the related gravity background, particularly in static and spherically symmetric wormhole spacetimes. These theoretical results can be used to detect the presence of a wormhole, distinguish it from a black hole, and reconstruct wormhole solutions through fitting observational data. The physical implications of the proposed epicyclic method are also discussed.
Article
Chemistry, Physical
A. Nagy
Summary: Recently, it has been shown that a set of spherically symmetric non-degenerate densities can uniquely determine the Coulomb external potential. This theory has been extended to degenerate states, where Euler equations and Kohn-Sham equations are derived, and a new form of the virial theorem is presented. It is highlighted that degenerate states of atoms can be treated rigorously as spherically symmetric when a subspace density with equal weighting factors is used.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Astronomy & Astrophysics
Antonio De Felice, Shinji Mukohyama, Masroor C. Pookkillath
Summary: Static, spherically symmetric solutions representing stars made of barotropic perfect fluid are studied in the context of two theories of type-II minimally modified gravity, VCDM and VCCDM. It is found that the solutions in V(C)CDM exactly coincide with the ones in GR.
Article
Physics, Particles & Fields
Marco Calza, Lorenzo Sebastiani
Summary: In this paper, we analyze a class of topological static spherically symmetric vacuum solutions in Q-gravity. We consider an Ansatz that ensures these solutions trivially satisfy the field equations when the non-metricity scalar is constant. Specifically, we provide and discuss local solutions in the form of black holes and traversable wormholes.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Nuclear
Moreshwar Tayde, Sayantan Ghosh, P. K. Sahoo
Summary: In this study, we analyze traversable wormhole solutions within the linear f(Q, T) = alpha Q + beta T gravity framework, ensuring the satisfaction of all energy conditions throughout spacetime. The solutions are obtained through a comprehensive analytical examination of the wormhole model's parameter space, considering the exponents governing redshift and shape functions, the wormhole throat radius (r(0)), redshift function value at the throat (phi(0)), and model parameters (alpha and beta). Bounds on these free parameters are established to guarantee energy condition satisfaction and provide two solutions. Additionally, the stability of a thin-shell around the wormhole is observed using the Israel junction condition. Finally, the null energy condition criteria and the potential for the thin-shell are calculated, along with their variations based on the chosen shape function.