Article
Physics, Mathematical
Daniel Berkowitz
Summary: By utilizing the Euclidean-signature semi-classical method, this study proves the existence of a countably infinite number of excited states for the Lorentzian-signature Taub-Wheeler-DeWitt equation in the presence of a cosmological constant. Additionally, a ground state solution is found when both an aligned electromagnetic field and cosmological constant are present. The method is also shown to be capable of proving solutions to Lorentzian-signature equations without needing to apply a Wick rotation, making it potentially useful for various problems in bosonic relativistic field theory and quantum gravity.
JOURNAL OF MATHEMATICAL PHYSICS
(2021)
Article
Astronomy & Astrophysics
Jean-Luc Lehners
Summary: Kontsevich and Segal proposed a criterion for determining allowable complex metrics, which has been suggested to apply to gravity as well. The study explored this criterion in the context of gravitational path integrals using simple models, finding that saddle points of the integrals lie at the edge of allowable metrics. The criterion also provides insight into the evolution of scalar fields in the context of the no-boundary proposal.
Article
Astronomy & Astrophysics
Nahomi Kan, Takuma Aoyama, Kiyoshi Shiraishi
Summary: This paper examines a bicosmology scenario proposed by Falomir et al., which introduces noncommutativity to solve cosmological problems. By considering exact classical solutions with constant noncommutativity and hypothesizing the appearance of noncommutativity when the scale factors are small, the researchers investigate the behavior of the model.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Article
Astronomy & Astrophysics
Bianca Dittrich, Steffen Gielen, Susanne Schander
Summary: This study employs the discrete (Lorentzian) Regge calculus to analyze Lorentzian quantum cosmology models, with a focus on discrete analogues of the no-boundary proposal for the early universe. The results show that using shells as a discretization method provides good agreement with continuum results, while the simple and subdivided four-polytope methods can only be compared with continuum results in certain cases.
CLASSICAL AND QUANTUM GRAVITY
(2022)
Article
Astronomy & Astrophysics
Hugo Garcia-Compean, Octavio Obregon, Cupatitzio Ramirez
Summary: This article reviews the work done by the authors and collaborators in the fields of supersymmetric quantum cosmology, noncommutative quantum cosmology, and the application of generalized uncertainty principles to quantum cosmology and black holes. The review is presented in chronological order and reflects the authors' personal views on the subjects.
Article
Quantum Science & Technology
Anirban Ganguly, Ritu Dhaulakhandi, Bikash K. Behera, Prasanta K. Panigrahi
Summary: Quantum computers offer a way to efficiently solve problems that conventional computers cannot handle. Quantum computational algorithms provide an exciting new method for studying quantum cosmology. By exploring minisuperspaces and using hybrid algorithms like VQE, researchers can analyze a wide range of cosmological models with implications for quantum gravity theories.
QUANTUM INFORMATION PROCESSING
(2021)
Article
Astronomy & Astrophysics
Fedele Lizzi, Patrizia Vitale
Summary: This passage discusses a specific noncommutative geometry known as angular or rho-Minkowski, which requires the spectrum of time to be discrete. In this space, the time variable does not commute with the angular variable in cylindrical coordinates, with possible values ranging from minus infinity to plus infinity equally spaced by the noncommutativity scale. The possible self-adjoint extensions of the time operator allow for time measurements to be any real value, but time intervals remain quantized.
Article
Physics, Multidisciplinary
Nurzada Beissen, Medeu Abishev, Manas Khassanov, Temirbolat Aitassov, Sagira Mamatova, Saken Toktarbay
Summary: This paper studies a specific isotropic and homogeneous cosmological model, analyzes the geometric properties of the model using the formalism of geometrothermodynamics, and derives the stability properties and phase transition structure of the cosmological model.
Article
Astronomy & Astrophysics
Mehdi Rezaei, Joan Sola Peracaula, Mohammad Malekjani
Summary: This study focuses on different types of dark energy models within the cosmographic approach, finding that the running vacuum models are preferred in cosmological analysis and are successful in alleviating cosmographic tensions in observational data.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Camila A. Correa, Matthieu Schaller, Sylvia Ploeckinger, Noemi Anau Montel, Christoph Weniger, Shin'ichiro Ando
Summary: We introduce the TangoSIDM project, a suite of cosmological simulations that explore the impact of large dark matter scattering cross-sections over dwarf galaxy scales. The simulations accurately model core formation and gravothermal core collapse, showing that the velocity-dependent cross-sections produce a large diversity in the circular velocities of satellite haloes. This research offers a promising explanation for the diversity in density and velocity profiles observed in dwarf galaxies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Review
Multidisciplinary Sciences
Leonardo Fernandez-Jambrina, Ruth Lazkoz
Summary: The article explores the different possible fates of the universe, including both singular and non-singular evolutions. The results are derived using generalized power and asymptotic expansions of the scale factor of the Universe.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Physics, Multidisciplinary
M. J. S. Houndjo, M. G. Ganiou, F. M. Kombetto, J. Tossa
Summary: In this paper, we investigate the f(T) theory of gravity coupled with scalar field and its reconstruction in the context of an exponential evolution of the scale factor. The impact of algebraic function on the slow-roll parameters is analyzed, and the results demonstrate the consistency of the reconstructed model with the recent data.
CHINESE JOURNAL OF PHYSICS
(2022)
Review
Astronomy & Astrophysics
Giulia Maniccia, Mariaveronica De Angelis, Giovanni Montani
Summary: This article analyzes the possibility of separating a gravity-matter system into a quasi-classical state and a small quantum subset using a WKB expansion of dynamics and considering the Bianchi universe minisuperspace. It discusses the validity of the approximation scheme for the Bianchi I model and explores applications for the quantum subsystem in the Bianchi IX model.
Article
Astronomy & Astrophysics
Chia -Min Lin
Summary: In this paper, we revisit D-term inflation and provide bounds on the cosmic string tension using gravitational wave observations. We also consider the possible deviation of the spectral index compared with the ΛCDM model in light of prerecombination resolutions of the Hubble tension. Our study shows that D-term inflation requires very small coupling constants under these constraints, and we demonstrate that natural coupling constants (g = A = 0.1) can be achieved in the case of D-term inflation on the brane.
Article
Astronomy & Astrophysics
H. R. M. Zarandi, E. Ebrahimi
Summary: This paper studies the cosmic age problem in holographic and generalized ghost dark energy models, and finds that non-linear interactions can alleviate the age problem. By analyzing age tests and data sets, the study also discovers a new bound for a parameter and shows that the generalized ghost dark energy can completely alleviate the cosmic age problem.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
J. Socorro, M. D'oleire, Luis O. Pimentel
ASTROPHYSICS AND SPACE SCIENCE
(2015)
Article
Physics, Particles & Fields
L. Toledo Sesma, J. Socorro, O. Loaiza
ADVANCES IN HIGH ENERGY PHYSICS
(2016)
Article
Physics, Multidisciplinary
J. Socorro, L. Toledo Sesma
EUROPEAN PHYSICAL JOURNAL PLUS
(2016)
Article
Physics, Particles & Fields
J. Socorro, L. Toledo Sesma, Luis O. Pimentel
ADVANCES IN HIGH ENERGY PHYSICS
(2018)
Article
Physics, Mathematical
J. Socorro, Omar E. Nunez, Rafael Hernandez-Jimenez
ADVANCES IN MATHEMATICAL PHYSICS
(2018)
Article
Astronomy & Astrophysics
Omar E. Nunez, J. Socorro, Rafael Hernandez-Jimenez
ASTROPHYSICS AND SPACE SCIENCE
(2019)
Article
Astronomy & Astrophysics
Luis Rey Diaz-Barron, Abraham Espinoza-Garcia, S. Perez-Payan, J. Socorro
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2020)
Article
Astronomy & Astrophysics
J. Socorro, S. Perez-Payan, Abraham Espinoza-Garcia, Luis Rey Diaz-Barron
ASTROPHYSICS AND SPACE SCIENCE
(2020)
Article
Astronomy & Astrophysics
J. Socorro, Omar E. Nunez, Rafael Hernandez-Jimenez
Article
Astronomy & Astrophysics
J. Socorro, Sinuhe Perez-Payan, Rafael Hernandez-Jimenez, Abraham Espinoza-Garcia, Luis Rey Diaz-Barron
Summary: This work investigates a flat Friedmann-Robertson-Walker Universe with two scalar fields, studying the effects of two potentials and a mixed momenta term on the solutions, leading to classical and quantum solutions for a quintom like case and a quintessence like case.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
Jose Socorro, Sinuhe Perez-Payan, Rafael Hernandez-Jimenez, Abraham Espinoza-Garcia, Luis Rey Diaz-Barron
Summary: In this paper, a chiral cosmological scenario is analyzed using the K-essence formalism. It is observed that the big-bang singularity can be explained by a big-bounce in certain conditions. The probability density of the classical subcases is computed through the analysis of the quantum counterpart.
Article
Astronomy & Astrophysics
J. Socorro, J. Juan Rosales
Summary: Using a specific quantum K-essence scalar field, we demonstrate the presence of a fractional differential equation in the scalar field variable within the quantum formalism, particularly in certain epochs of the FLRW model. In classical analysis, the kinetic energy of scalar fields can falsify standard matter and provide similar results to the algebraic procedures in the Einstein field equations. The quantum Wheeler-DeWitt equation yields a fractional differential equation with an order proportional to/ 2 proportional to-1, and the corresponding quantum solutions are provided.
Article
Astronomy & Astrophysics
Luis Rey Diaz-Barron, Abraham Espinoza-Garcia, S. Perez-Payan, J. Socorro
Summary: The researchers constructed a noncommutative scheme for a homogeneous scalar field and found that the characteristic big bounce of Loop Quantum Cosmology is preserved. Numerical solutions for the quadratic case showed an early inflationary period.
Proceedings Paper
Astronomy & Astrophysics
J. Socorro, L. Toledo Sesma, L. O. Pimentel
XI MEXICAN SCHOOL ON GRAVITATION AND MATHEMATICAL PHYSICS, QUANTUM GRAVITY: SCHEMES, MODELS AND PHENOMENOLOGY
(2018)
Proceedings Paper
Physics, Mathematical
J. Socorro, M. D'oleire, Luis O. Pimentel
X MEXICAN SCHOOL ON GRAVITATION AND MATHEMATICAL PHYSICS: ''REACHING A CENTURY: CLASSICAL AND MODIFIED GENERAL RELATIVITY'S ATTEMPTS TO EXPLAIN DE EVOLUTION OF THE UNIVERSE''
(2015)
Article
Astronomy & Astrophysics
Nelson R. F. Braga, Octavio C. Junqueira
Summary: This study investigates the influence of rotation on the transition temperature of strongly interacting matter produced in non-central heavy ion collisions. By using a holographic description of an AdS black hole, the authors extend the analysis to the more realistic case where the matter spreads over a region around the rotational axis. The results show the coexistence of confined and deconfined phases and are consistent with the concept of local temperature in rotating frames developed by Tolman and Ehrenfest.
Article
Astronomy & Astrophysics
Bing Sun, Jiachen An, Zhoujian Cao
Summary: This paper investigates the effect of gravitational constant variation on the propagation of gravitational waves. By employing two analytical methods, the study finds that variations in the gravitational constant result in amplitude and phase corrections for gravitational waves, and the time variation of the gravitational constant can be constrained through the propagation of gravitational waves.
Article
Astronomy & Astrophysics
Abdellah Touati, Zaim Slimane
Summary: This letter presents the first study of Hawking radiation as a tunneling process within the framework of non-commutative gauge theory of gravity. The non-commutative Schwarzschild black hole is reconstructed using the Seiberg-Witten map and the star product. The emission spectrum of outgoing massless particles is computed using the quantum tunneling mechanism. The results reveal pure thermal radiation in the low-frequency scenario, but a deviation from pure thermal radiation in the high-frequency scenario due to energy conservation. It is also found that noncommutativity enhances the correlations between successively emitted particles.
Article
Astronomy & Astrophysics
Shahar Hod
Summary: The travel times of light signals between two antipodal points on a compact star's surface are calculated for two different trajectories. It is shown that, for highly dense stars, the longer trajectory along the surface may have a shorter travel time as measured by asymptotic observers. A critical value of the dimensionless density-area parameter is determined for constant density stars to distinguish cases where crossing through the star's center or following a semi-circular trajectory on the surface has a shorter travel time as measured by asymptotic observers.
