Article
Astronomy & Astrophysics
Salvatore Capozziello, Nisha Godani
Summary: Non-local gravity is considered to obtain stable and traversable wormhole solutions. By studying the class of Non-local Integral Kernel Theories of Gravity, constraints for the null energy condition and field equations are derived. The main result is that non-local gravity contributions allow for the stability and traversability of the wormhole without the need for exotic matter.
Article
Astronomy & Astrophysics
Milko Estrada, C. R. Muniz
Summary: In this paper, new d-dimensional and asymptotically flat wormhole solutions are obtained by assuming a specific form of the energy density distribution. Constraints for the involved parameters are found to build those wormholes. The properties of the obtained solutions, including embedding diagrams as well as Weak and Null Energy Conditions (WEC and NEC), are studied and it is shown that the violations of these energy conditions become more pronounced with larger spacetime dimension.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Merce Guerrero, Gonzalo J. Olmo, Diego Rubiera-Garcia
Summary: This study examines reflection-asymmetric thin-shell wormholes within Palatini f(R) gravity and establishes conditions for stable wormholes supported by positive-energy matter sources. It also identifies parameter subsets for positioning the shell radius above the event horizon but below the photon sphere. Additionally, it demonstrates the phenomenon of two photon spheres allowing observers to see double shadows due to the effective potential on each side of the wormhole.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Jan Ambjorn, Yuki Hiraga, Yoshiyasu Ito, Yuki Sato
Summary: By quantizing the two-dimensional projectable Horava-Lifshitz gravity with bi-local and spacelike wormhole interaction, we find that the resulting quantum Hamiltonian coincides with that obtained through summing over all genus in the string field theory, implying that the wormhole interaction can be interpreted as a splitting or joining interaction of one-dimensional strings.
Article
Astronomy & Astrophysics
Takol Tangphati, C. R. Muniz, Anirudh Pradhan, Ayan Banerjee
Summary: This paper investigates the existence of asymptotically flat wormhole geometries within the framework of Rastall-Rainbow modified gravity. It demonstrates that static and spherically symmetric wormholes cannot emerge in a zero-tidal-force context under specific combinations of free parameters and equations of state. By evaluating the stability of viable solutions through adiabatic sound velocity analysis and examining their compliance with the Weak Energy Condition (WEC), the study provides insights into how the interplay between Rastall parameters and Rainbow functions may alleviate violations of energy conditions in these modified gravity scenarios.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Physics, Particles & Fields
Yiming Chen, Victor Gorbenko, Juan Maldacena
Summary: This text discusses two-dimensional CFT states produced by gravitational path integrals, focusing on cases of Euclidean AdS(2) evolution and Lorentzian dS(2) evolution followed by flat space evolution. It is found that naive hyperbolic space geometry leads to paradoxes, which can be resolved by incorporating bra-ket wormholes. Despite issues with divergent temperatures, projection onto low energy states reveals similarities with the previous Euclidean case, suggesting a connection between maximum entropy and de Sitter entropy.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Vivek Sharma, Suman Ghosh
Summary: This study examines a model where the GEB wormhole geometry is embedded in a five-dimensional warped background, and analyzes the status of all energy conditions in EB and GEB embeddings in detail. The presence of a decaying warp factor leads to the satisfaction of weak energy conditions, and the improvement of other energy conditions compared to the four-dimensional scenario is also observed.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
A. Bakopoulos, C. Charmousis, P. Kanti
Summary: In this study, we construct a large class of explicit, asymptotically flat and regular wormhole solutions in higher order scalar tensor theories. These solutions are obtained through a general disformal transformation of a seed black hole solution. The wormholes are parametrized by their ADM mass and two coupling constants of the theory, one related to their higher dimensional Lovelock origin and one to the disformal transformation itself.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
M. Yousaf, M. Z. Bhatti, Z. Yousaf
Summary: This manuscript investigates the construction of static cylindrically symmetric thin shell wormhole models with an electric charge in the background of f(R, T) gravity. The study finds that a charged wormhole model may be more stable than an uncharged one.
Article
Physics, Multidisciplinary
Z. Yousaf, M. Z. Bhatti, M. Rasheed
Summary: This manuscript constructs a spherical thin shell wormhole in the background of the minimally coupled f(R, T) model, using a cut and paste approach to link interior and exterior surfaces. The energy-momentum density and surface pressure for the f(R, T) = R + αR^2 + λT model are found using the Lanczos equation, and the dynamical behavior of the wormhole is checked using the polytropic equation of state. The stability of the constructed wormhole with throat radius a(0) is examined using a standard potential approach, with graphical analysis showing that stability regions depend on the specific values of the mass to charge ratio.
Article
Astronomy & Astrophysics
Riccardo Della Monica, Ivan de Martino
Summary: Despite the improvements in future observations, it remains difficult to determine whether the central supermassive object is a black hole or a wormhole. The study used data from the S0-2 star and simulated observations to investigate the nature of the object, but was unable to definitively distinguish between the two possibilities. However, it was found that stars orbiting closer to the object could provide valuable insights into its fundamental nature.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
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
M. Khlopunov, D. V. Gal'tsov
Summary: In the DGP model, the instability of the graviton leads to a modification of gravity at cosmological distances, resulting in the leakage of gravitational waves into an extra dimension. The calculation of the leakage intensity is challenging due to the violation of the Huygens principle in the five-dimensional bulk of the model. In this paper, a simplified problem of scalar radiation from a point charge localized on a brane in the framework of the scalar field analog of the DGP model is considered. The radiated part of the field is extracted using a generalized approach, and the dependence of the leakage intensity on the sphere radius is obtained. The results suggest that the leakage intensity is higher for low frequency signals. The possibility of detecting this leakage using gravitational-wave observatories is also analyzed.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Kohki Kawabata, Tatsuma Nishioka, Yoshitaka Okuyama, Kento Watanabe
Summary: The entanglement capacity is considered as a probe of Hawking radiation in a two-dimensional dilaton gravity system coupled with large degrees of freedom conformal matter. A formula for calculating the capacity is derived using the gravitational path integral, suggesting a discontinuity at the Page time. Application of the formula to a replica wormhole solution in an eternal AdS black hole coupled to a non-gravitating bath revealed saturation of the entanglement capacity by the thermal capacity of the black hole in the high temperature limit.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
A. Bonanno, S. Silveravalle, A. Zuccotti
Summary: A new type of asymptotically flat wormhole, characterized by a Newtonian potential with a Yukawa correction in its outer spacetime and possessing a singularity at r = ??? in its internal spacetime, has been studied. Geodesics reaching this singularity exhibit a divergence in the expansion scalar in a finite amount of proper time, resembling the future singularity of the big rip cosmological scenario. These wormholes fill a large region of the parameter space of physical solutions.
Article
Physics, Particles & Fields
Luis P. Chimento, Martin G. Richarte
EUROPEAN PHYSICAL JOURNAL C
(2013)
Article
Physics, Particles & Fields
Luis P. Chimento, Monica Forte, Martin G. Richarte
EUROPEAN PHYSICAL JOURNAL C
(2013)
Article
Physics, Particles & Fields
Luis P. Chimento, Martin G. Richarte
EUROPEAN PHYSICAL JOURNAL C
(2013)
Article
Astronomy & Astrophysics
Luis P. Chimento, Monica Forte, Martin G. Richarte
MODERN PHYSICS LETTERS A
(2013)
Article
Astronomy & Astrophysics
Luis P. Chimento, Martin G. Richarte, Ivan E. Sanchez
MODERN PHYSICS LETTERS A
(2013)
Article
Astronomy & Astrophysics
Luis P. Chimento, Ruth Lazkoz, Martin G. Richarte
Article
Astronomy & Astrophysics
Luis P. Chimento, Martin G. Richarte
Article
Astronomy & Astrophysics
Luis P. Chimento, Martin G. Richarte
Article
Astronomy & Astrophysics
Martin G. Richarte
Article
Physics, Multidisciplinary
Iarley P. Lobo, Martin G. Richarte, J. P. Morais Graca, H. Moradpour
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.
Proceedings Paper
Astronomy & Astrophysics
Luis P. Chimento, Monica I. Forte, Martin G. Richarte
I COSMOSUL: COSMOLOGY AND GRAVITATION IN THE SOUTHERN CONE
(2012)
Proceedings Paper
Astronomy & Astrophysics
Luis P. Chimento, Martin G. Richarte
I COSMOSUL: COSMOLOGY AND GRAVITATION IN THE SOUTHERN CONE
(2012)
