Article
Astronomy & Astrophysics
Daniele Oriti, Xiankai Pang
Summary: The analysis of emergent cosmological dynamics in mean field hydrodynamics of quantum gravity condensates reveals accelerated expansion of the universe at both early and late times. Although it does not support a compelling inflationary scenario in the early universe, it naturally produces a phantom-like dark energy dynamics at late times, which crosses the phantom divide and avoids any Big Rip singularity, approaching a de Sitter universe asymptotically.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Denis Comelli, Maicol Di Giambattista, Luigi Pilo
Summary: Gyroscopic systems in classical and quantum field theory are characterized by the presence of scalar degrees of freedom and terms that mix fields and their time derivatives. These systems can arise from the coupling among fields with time-dependent and space-dependent vacuum expectation values, and can exhibit stability in certain parameter spaces.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
S. Capozziello, S. Zare, D. F. Mota, H. Hassanabadi
Summary: In this study, the effects of a dark matter spike near the supermassive black hole in M87 (Virgo A galaxy) were investigated using the Bumblebee Gravity theory. The aim was to determine the impact of spontaneous Lorentz symmetry breaking on the horizon, ergo-region, and shadow of the Kerr Bumblebee black hole in the spike region. Dark matter distribution was incorporated into a Lorentz-violating spherically symmetric space-time, and the resulting solution was generalized to a Kerr Bumblebee black hole. The shapes of the shadow were examined based on observational data for the dark matter spike density and radius.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Multidisciplinary Sciences
Herbert W. Hamber, Lu Heng Sunny Yu
Summary: The passage discusses the perturbative nature of gravity theory, the use of the Hartree-Fock approximation for quantum gravity, and the resulting self-consistent integral equations for graviton self-energy. The nonlinear equations for graviton self-energy in the Hartree-Fock approximation show distinct features compared to scalar and gauge theory cases, revealing a nontrivial ultraviolet fixed point and scaling dimensions in certain spacetime dimensions. Additionally, the Hartree-Fock approximation provides an explicit analytic expression for the renormalization group running of Newton's constant, suggesting gravitational antiscreening behavior.
Article
Astronomy & Astrophysics
Giovanni Gandolfi, Andrea Lapi, Stefano Liberati
Summary: The study focuses on self-gravitating equilibria of dark matter (DM) halos with non-minimal coupling to gravity, which results in the development of an inner core and a shape closely following the Burkert profile. This non-minimal coupling allows for mass distribution that fits well with rotation curves of dwarf, DM-dominated galaxies and is consistent with observed scaling relations among different galaxies.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
James Page, Joao Magueijo
Summary: This study revisits a mechanism proposed by Hawking to address the cosmological constant problem and offers alternative solutions. By introducing a new action coupling the four-form field strength to the cosmological constant, a novel mechanism similar to Unimodular Gravity is presented. A theory with a similar coupling is also discussed, showing promising results and proposing new interpretations related to time and probability flux.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Tom Rudelius
Summary: A popular proposal for resolving the Hubble tension involves early dark energy models driven by an axion field. However, these models are tightly constrained by the axion weak gravity conjecture, making it challenging to realize them in a UV complete theory of quantum gravity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Reginald Christian Bernardo, Che-Yu Chen, Jackson Levi Said, Yu-Hsien Kung
Summary: This study investigates the effects of quantum fluctuations on the late Universe and explores a representative model with quantum fluctuations embedded in modified gravitational theories. The results suggest mild support for quantum corrections in cosmological models.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Hassan Firouzjahi, Mohammad Ali Gorji, Shinji Mukohyama, Borna Salehian
Summary: The model introduces a scenario of vector dark matter production during inflation, where the quantum fluctuations of the inflaton field energy are used to explain the observed relic density of dark matter, which can be applicable to a wide range of parameters.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Multidisciplinary
Maryam Roushan, Narges Rashidi, Kourosh Nozari
Summary: Quantum gravitational effects are not only important on small scales but also significant on cosmological scales. The existence of a minimal measurable momentum plays a crucial role in the accelerating expansion of the universe.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Physics, Particles & Fields
Borna Salehian, Hong-Yi Zhang, Mustafa A. Amin, David Kaiser, Mohammad Hossein Namjoo
Summary: This paper systematically derives the SP equations and relativistic corrections from the nonlinear and fully relativistic KGE equations in an expanding universe, providing insights into deviations and applicability beyond the SP system. The method presented simplifies the analysis of scalar dark matter dynamics and accurately captures deviations from the SP system towards the full KGE case, particularly in calculating the mass-radius relationship of solitons.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Sukanta Panda, Abbas Altafhussain Tinwala, Archit Vidyarthi
Summary: We investigate the quantum stability of generalised Proca theories in curved spacetime treating gravity as a dynamical field. By evaluating the divergent part of the effective action at one-loop level using Vilkovisky-DeWitt formalism, we find that quantum corrections are suppressed by a UV cutoff parametrically higher than the Proca mass when the coupling constants are restricted to a certain range. Furthermore, we show that quantum corrections remain suppressed even at scales where classical non-linearities dominate over kinetic terms, allowing the Vainshtein mechanism to work effectively.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Bartlomiej Kiczek, Marek Rogatko, Karol Wysokinski
Summary: Using the gauge-gravity duality to explore the properties of a holographic superconducting quantum device influenced by dark matter, researchers have observed a small but visible effect on the device's maximal current when a dark matter particle traverses it.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Alexander B. Balakin, Alexei S. Ilin
Summary: We propose a new self-consistent model that couples cosmic dark energy and dark matter using the rheological approach. This model represents the equations of state as integral operators of the Volterra type. We classify the exact solutions of the model based on the roots of the characteristic polynomial. The pressure, energy density, Hubble function, and acceleration parameter of dark energy and dark matter are expressed explicitly as functions of the dimensionless scale factor. We discuss two intriguing cosmological solutions that describe superexponential expansion and symmetric bounce, as well as new solutions corresponding to quasiperiodic behavior.
Review
Astronomy & Astrophysics
Veronica Motta, Miguel A. Garcia-Aspeitia, Alberto Hernandez-Almada, Juan Magana, Tomas Verdugo
Summary: The article summarizes the characteristics of dark energy models and some commonly used cosmological samples, discusses how to constrain model parameters using observational data, and finally provides an overview of the status of dark energy modeling.
Article
Engineering, Aerospace
Dusko Borka, Vesna Borka Jovanovic, Salvatore Capozziello, Predrag Jovanovic
Summary: We study the velocity distribution of elliptical galaxies within the framework of Non-local Gravity. This approach allows us to reproduce the fundamental plane of elliptical galaxies without assuming the presence of dark matter. By comparing theoretical predictions with observed data, we find that non-local gravity effects can successfully explain the stellar dynamics in elliptical galaxies.
ADVANCES IN SPACE RESEARCH
(2023)
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
Astronomy & Astrophysics
David Benisty, Salvatore Capozziello
Summary: In this study, the dynamics of the Local Group (LG) of galaxies were examined with regards to contributions from the cosmological constant. The effects of dark energy and dark matter in the f(R) gravity theory were considered in the analysis. Constraints on the Yukawa couplings were derived, and the possibility of replacing dark matter with a MOND-like theory was explored. The study also demonstrated the potential of falsifying MOND-like theories through the calculation of the dark matter to baryonic matter ratio in the LG.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Astronomy & Astrophysics
Filippo Bouche, Salvatore Capozziello, Vincenzo Salzano
Summary: Alternative cosmological models are being studied as potential solutions to the weaknesses of the lambda CDM model. Tensions have emerged between the model-dependent analysis of the Cosmic Microwave Background and lower redshift probes as cosmological surveys improve. Two quantum-inspired non-locally extended theories of gravity are reviewed, focusing on their cosmological implications and their potential to address the Hubble and growth tensions. The Deser-Woodard model shows promising features, while further investigation is needed for the non-local cosmology based on Noether symmetries.
Article
Astronomy & Astrophysics
M. G. Dainotti, G. Bargiacchi, A. L. Lenart, S. Nagataki, S. Capozziello
Summary: Currently, the cold dark matter model along with a cosmological constant is the best representation of the universe. However, we lack information in the high-redshift region and the study of quasars up to z = 7.54 has provided important insights into the matter density parameter omega( M ). This demonstrates the reliability of quasars as standard cosmological candles.
ASTROPHYSICAL JOURNAL
(2023)
Article
Physics, Multidisciplinary
Stefano Camera, Salvatore Capozziello, Lorenzo Fatibene, Andrea Orizzonte
Summary: We investigate how the cosmological equation of state can be used to scrutinize extended theories of gravity, specifically the Palatini f(R) gravity. The effective equation of state produced by a given model is studied, and the inverse problem of determining which models are compatible with a given effective equation of state is also considered. We find that power-law models are capable of transforming barotropic Equations of State into effective barotropic ones, and the form of equation of state is preserved only for f(R) = R. Additionally, quadratic and non-homogeneous effective Equations of State contain the Starobinsky model and other models.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Astronomy & Astrophysics
Maria Giovanna Dainotti, Giada Bargiacchi, Malgorzata Bogdan, Aleksander Lukasz Lenart, Kazunari Iwasaki, Salvatore Capozziello, Bing Zhang, Nissim Fraija
Summary: By combining high-redshift probes such as GRBs and QSOs with other observational data, it is shown that alternative cosmological models could potentially explain the discrepancy in the Hubble constant. This study uses data from GRBs and QSOs, and applies statistical methods to reduce uncertainties in the estimation of cosmological parameters.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Salvatore Capozziello, Gamal G. L. Nashed
Summary: We derive a novel class of four-dimensional black hole solutions in Gauss-Bonnet gravity coupled with a scalar field in the presence of Maxwell electrodynamics. The choice of metric ansatz and the presence of the scalar field lead to the emergence of higher-order terms and the creation of monopoles in the metric potentials. The computed invariants associated with the black holes show soft singularities and the solutions exhibit multiple horizons depending on the spacetime.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Multidisciplinary Sciences
Francesco Bajardi, Salvatore Capozziello, Tiziana Di Salvo, Francesca Spinnato
Summary: The Noether Symmetry Approach is a method for solving the dynamics of physical systems by selecting symmetries. It can be applied in various fields and is useful for selecting viable models and finding exact solutions.
Article
Astronomy & Astrophysics
G. G. L. Nashed, S. Capozziello
Summary: This study investigates the possible modifications of general relativity at ultraviolet and infrared scales, particularly considering the possibility of parity violation in strong gravity regime. The Chern-Simons gravity theory is used to account for the parity violation. The study shows that for certain spacetime structures, Chern-Simons gravity is equivalent to general relativity, but it is not applicable to (A)dS-Kerr/Kerr black holes. The thermodynamic quantities and geodesic equation of the black hole are also calculated.
Article
Astronomy & Astrophysics
M. G. Dainotti, A. L. Lenart, A. Chraya, G. Sarracino, S. Nagataki, N. Fraija, S. Capozziello, M. Bogdan
Summary: Currently, there is a debate about cosmological models and their corresponding parameters due to the discrepancy between H-0 obtained from SNe Ia and the Planck data. Considering high redshift probes like gamma-ray bursts (GRBs) is necessary but challenging due to the large range of GRB luminosities. In this study, we use the 3D Dainotti fundamental plane relation to infer cosmological parameters, and by considering selection and evolutionary effects, we obtain a lower intrinsic scatter compared to previous results. Our analysis, using GRB correlations and complemented with SNe Ia and BAO measurements, confirms the parameters of the Lambda cold dark matter model but with the advantage of using probes detected up to z = 5.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Physics, Particles & Fields
Salvatore Capozziello, Rocco D'Agostino, Alessio Lapponi, Orlando Luongo
Summary: We demonstrate the existence of black hole solutions that conform to the thermodynamics of logotropic fluids, which have recently been employed to address cosmological and astrophysical issues, within the framework of the Einstein field equations with a negative cosmological constant. This is accomplished by employing the generalization of logotropic fluids known as the Anton-Schmidt equation of state. We further investigate the construction of the anti-de Sitter metric, satisfying energy conditions, and explore alternative solutions by relaxing the strong energy condition.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Astronomy & Astrophysics
Salvatore Capozziello, Rocco D'Agostino
Summary: This article explores non-local modifications of General Relativity by considering a distortion function in terms of the inverse of the d'Alembert operator. By using numerical methods and a model-independent approach based on current observations, the shape of the distortion function is reconstructed, and the best analytical approximation of the non-local Lagrangian is inferred. The results show that this non-local modification provides a natural explanation for late cosmic acceleration and avoids fine-tuning issues with the cosmological constant.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Physics, Particles & Fields
Salvatore Capozziello, Vittorio De Falco, Carmen Ferrara
Summary: In the context of metric-affine gravity, the role of the boundary term in Symmetric Teleparallel Gravity is examined in f(Q,B) models. The field equations are derived and compared to those of f(Q) gravity in the limit of B approaching 0, revealing the dynamic equivalence between f(Q,B) and f(R) gravity. Conservation laws are also obtained. Considering boundary terms in f(Q) gravity represents the final ingredient for the Extended Geometric Trinity of Gravity, allowing for a unified treatment of f(R), f(T,(B) over tilde), and f(Q,B).
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Quantum Science & Technology
Carlo Altucci, Francesco Bajardi, Andrea Basti, Nicolo Beverini, Giorgio Carelli, Salvatore Capozziello, Simone Castellano, Donatella Ciampini, Fabrizio Davi, Francesco dell'Isola, Gaetano De Luca, Roberto Devoti, Giuseppe Di Somma, Angela D. V. Di Virgilio, Francesco Fuso, Ivan Giorgio, Aladino Govoni, Enrico Maccioni, Paolo Marsili, Antonello Ortolan, Alberto Porzio, Matteo Luca Ruggiero, Raffaele Velotta
Summary: The GINGER project aims to construct an array of three large frame ring laser gyroscopes with high sensitivity to measure angular velocity with respect to the fixed stars and provide geophysical investigation data.
AVS QUANTUM SCIENCE
(2023)
