Article
Mathematics, Interdisciplinary Applications
Jaume Llibre
Summary: We studied the dynamics of the Bianchi IX universe and its relation to the Bianchi VII universe. The analysis showed the presence of a surface filled with periodic orbits and equilibrium points, while other orbits tend towards infinity.
CHAOS SOLITONS & FRACTALS
(2022)
Article
Physics, Particles & Fields
Elham Ghorani, Yaghoub Heydarzade
Summary: The emergent universe scenario proposes a nonsingular static origin of the Universe to resolve the Big Bang singularity problem in standard cosmology. This study explores the possibility of a nonsingular Kantowski-Sachs type static state, showing that its existence and stability depend on spacetime dimensions and the nature of the supporting fluid in four and five dimensional models.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Physics, Multidisciplinary
M. Sharif, M. Zeeshan Gul
Summary: This paper analyzes the stability of the closed Einstein static universe using linear homogeneous perturbations in the framework of energy-momentum squared gravity, showing that stable regions in this modified theory are large compared to other modified theories of gravity.
Article
Quantum Science & Technology
King Lun Ng, Bogdan Opanchuk, Manushan Thenabadu, Margaret Reid, Peter D. Drummond
Summary: This paper discusses the feasibility of studying false vacuum tunneling using a BEC quantum simulator, observing false vacuum tunneling and the formation of multiple bubble universes with distinct topological properties. By analyzing the topological phase entropy, a model for the formation of universes with two distinct phases in the true vacuum is proposed.
Article
Physics, Multidisciplinary
Jose Edgar Madriz Aguilar, J. Zamarripa, M. Montes, J. A. Licea, C. De Loza, A. Peraza
Summary: In this paper, we propose a method to extend some Lambda(t)-CDM models to the inflationary period by assuming a 5D quantum pre-inflationary vacuum energy and using dynamical foliations of the 5D Ricci-flat space-time manifold. This approach allows for a geometrical unification of inflation and the present accelerating epoch. The inflation is generated by a pre-inflationary quantum vacuum energy that maintains the 5D classical vacuum on cosmological scales. The model also predicts certain values for the spectral index and scalar-to-tensor ratio that fit well with Planck 2018 results.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Engineering, Multidisciplinary
Mustafa Inc, Muhammad S. Iqbal, Muhammad Z. Baber, Muhammad Qasim, Zafar Iqbal, Muhammad Akhtar Tarar, Ali Hasan Ali
Summary: This study investigates Einstein's vacuum field equation analytically to explore solitary wave solutions. The equation is significant in mathematical physics and has meaningful applications in general relativity. The research uses generalized exponential rational function and modified auxiliary equation approaches to obtain exact solitary wave solutions and conducts stability analysis. The results demonstrate the effectiveness of applying these methods in resolving nonlinear issues in science and technology.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
Article
Astronomy & Astrophysics
Marco Bruni, Rodrigo Maier, David Wands
Summary: This study examines the dynamics of Friedmann-Lemaitre-Robertson-Walker cosmologies with an interaction between vacuum and perfect fluid through energy exchange. The focus is on exploring nonsingular configurations, including cyclic and bouncing models. The research demonstrates that both linear and nonlinear combinations of vacuum and fluid energy densities can lead to bouncing and cycling cosmologies.
Article
Physics, Multidisciplinary
Zahra Amirabi
Summary: We construct a generic thin-shell wormhole (TSW) in the Robertson-Walker (RW) cosmological model of the Universe. In this paper, we investigate the stability of the TSW constructed in the static RW universe by performing two different stability analyses. The results show that the TSW is stable against a linear radial perturbation and the throat of the TSW oscillates between the center of the Universe and the outer boundary under small-speed perturbation.
Article
Mathematics
Zhimeng Ouyang, Lei Wu
Summary: We consider the non-relativistic quantum Boltzmann equation for fermions and bosons, and using the nonlinear energy method and mild formulation, we prove the global well-posedness under the condition that the density function is near the global Maxwellian and vacuum. This work is a generalization and adaptation of the classical Boltzmann theory, and our main contribution lies in the detailed analysis of the nonlinear operator Q in the quantum context. It is the first part of a long-term project on quantum kinetic equations.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2022)
Article
Mathematics
Seungsu Hwang, Gabjin Yun
Summary: This paper examines vacuum static spaces with the complete divergence of the Bach tensor and Weyl tensor, proving certain properties of the metric under different conditions, such as metric harmonicity and Bach flatness. It also establishes some conjectures and provides sufficient conditions for the metric to be Bach-flat.
JOURNAL OF GEOMETRIC ANALYSIS
(2021)
Article
Astronomy & Astrophysics
Herondy F. S. Mota, Celio R. Muniz, Valdir B. Bezerra
Summary: This paper investigates the thermal fluctuation corrections to the vacuum energy at zero temperature of a conformally coupled massless scalar field in the Einstein universe with a spherical boundary. The results generalize those found in previous literature and calculate the renormalized Casimir free energy, internal energy, and entropy, considering both high and low temperature limits. The study reveals classical contributions along with logarithmic terms at high temperatures, while at low temperatures, the vacuum energy dominates and the entropy obeys the third law of thermodynamics.
Article
Physics, Multidisciplinary
M. Sharif, M. Zeeshan Gul
Summary: This paper studies the stability of the Einstein static Universe against anisotropic homogeneous perturbations in energy-momentum squared gravity. By analyzing specific models, it is found that stable solutions exist under certain parameter conditions, and compared to other alternative gravitational theories, the stable solutions increase.
PRAMANA-JOURNAL OF PHYSICS
(2022)
Article
Astronomy & Astrophysics
Asanka Amarasinghe, Tianye Liu, Daniel A. Norman, Philip D. Mannheim
Summary: This paper investigates cosmological perturbation theory in the context of the fourth-order derivative conformal gravity theory and provides an exact solution from the recombination era until the present era.
Article
Multidisciplinary Sciences
Irina Radinschi, Theophanes Grammenos, Gargee Chakraborty, Surajit Chattopadhyay, Marius Mihai Cazacu
Summary: The energy-momentum localization for the four-dimensional static and spherically symmetric, regular Simpson-Visser black hole solution is studied. It is found that all momenta vanish and the energy distribution depends on the parameters of the metric, with potential applications to astrophysical issues related to gravitational lensing.
Article
Astronomy & Astrophysics
Chao Liu, Yiqing Shi
Summary: This article investigates the nonlinear Jeans instability and develops a method for proving the Jeans instability for slightly nonlinear Euler-Poisson equations. The traditional Fourier analysis method is difficult to generalize to a nonlinear setting, so a non-Fourier method is proposed. The research on the fully nonlinear Jeans instability for the Euler-Poisson and Einstein-Euler equations is still ongoing.
Article
Astronomy & Astrophysics
G. Martinez-Solaeche, R. M. Gonzalez Delgado, R. Garcia-Benito, A. de Amorim, E. Perez, J. E. Rodriguez-Martin, L. A. Diaz-Garcia, R. Cid Fernandes, C. Lopez-Sanjuan, S. Bonoli, A. J. Cenarro, R. A. Dupke, A. Marin-Franch, J. Varela, H. Vazquez Ramio, L. R. Abramo, D. Cristobal-Hornillos, M. Moles, J. Alcaniz, P. O. Baqui, N. Benitez, S. Carneiro, A. Cortesi, A. Ederoclite, V Marra, C. Mendes de Oliveira, L. Sodre, J. M. Vilchez, K. Taylor
Summary: This paper presents a new method based on artificial neural networks for measuring and detecting emission lines in galaxies, essential for understanding cosmic evolution. The study demonstrates the value of ANNs in surveys like J-PAS and their capability to overcome limitations in emission line detection and measurements.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
P. O. Baqui, V. Marra, L. Casarini, R. Angulo, L. A. Diaz-Garcia, C. Hernandez-Monteagudo, P. A. A. Lopes, C. Lopez-Sanjuan, D. Muniesa, V. M. Placco, M. Quartin, C. Queiroz, D. Sobral, E. Solano, E. Tempel, J. Varela, J. M. Vilchez, R. Abramo, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, A. J. Cenarro, D. Cristobal-Hornillos, A. L. de Amorim, C. M. de Oliveira, R. Dupke, A. Ederoclite, R. M. Gonzalez Delgado, A. Marin-Franch, M. Moles, H. Vazquez Ramio, L. Sodre, K. Taylor
Summary: In this work, the authors discuss the classification of miniJPAS sources into extended (galaxies) and point-like (e.g., stars) objects, aiming to develop a complementary ML classifier to traditional tools for subsequent scientific analyses. They trained and tested six different ML algorithms on cross-matched catalogs and found that random forest (RF) and extremely randomized trees (ERT) algorithms performed best, achieving high AUC values when using both photometric and morphological information together.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Cassio Pigozzo, Flora S. Bacelar, Saulo Carneiro
Summary: In Loop Quantum Gravity (LQG), the quantization of general relativity provides precise predictions for geometrical observables and successfully derives the Bekenstein-Hawking entropy of large black holes. The value of the Barbero-Immirzi (BI) parameter is fixed at a specific limit, with evidence suggesting that black holes with certain angular momentum and mass may be eigenstates of the area operator.
CLASSICAL AND QUANTUM GRAVITY
(2021)
Article
Astronomy & Astrophysics
J. Chaves-Montero, S. Bonoli, B. Trakhtenbrot, A. Fernandez-Centeno, C. Queiroz, L. A. Diaz-Garcia, R. M. Gonzalez Delgado, A. Hernan-Caballero, C. Hernandez-Monteagudo, C. Lopen-Sanjuan, R. Overzier, D. Sobral, L. R. Abramo, J. Alcaniz, N. Benitez, S. Carneiro, A. J. Cenarro, D. Cristobal-Hornillos, R. A. Dupke, A. Ederoclite, A. Marin-Franch, C. Mendes de Oliveira, M. Moles, L. Sodre Jr, K. Taylor, J. Varela, H. Vazquez Ramio, T. Civera
Summary: This study develops a novel method for calculating black hole masses using measurements of continuum luminosities and emission line widths from narrow-band observations. The results show that this technique can achieve similar precision to single-epoch spectroscopy. The findings of this research are important for exploring the physical properties of quasar populations that do not meet the preselection criteria of previous spectroscopic surveys.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Saulo Carneiro, Cassio Pigozzo
Summary: It is argued that the quantum of area between consecutive, high overtones quasinormal modes of a black hole horizon coincides with the area gap predicted by Loop Quantum Gravity, as long as the horizon is isolated and the Barbero-Immirzi parameter is gamma approximate to root 3/6 in agreement with the value derived from the Bekenstein-Hawking horizon entropy.
GENERAL RELATIVITY AND GRAVITATION
(2022)
Correction
Astronomy & Astrophysics
Saulo Carneiro, Cassio Pigozzo
GENERAL RELATIVITY AND GRAVITATION
(2022)
Article
Physics, Multidisciplinary
S. Carneiro, C. Pigozzo, J. S. Alcaniz
Summary: Recent studies found that a small error in type Ia supernovae measurements can affect the estimation of cosmological parameters, particularly when low-redshift supernovae are included. This can result in a reduction of approximately 5% in the value of the local Hubble constant.
EUROPEAN PHYSICAL JOURNAL PLUS
(2022)
Article
Astronomy & Astrophysics
C. Lopez-Sanjuan, P-E Tremblay, A. Ederoclite, H. Vazquez Ramio, A. J. Cenarro, A. Marin-Franch, J. Varela, S. Akras, M. A. Guerrero, F. M. Jimenez-Esteban, R. Lopes de Oliveira, A. L. Chies-Santos, J. A. Fernandez-Ontiveros, R. Abramo, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, D. Cristobal-Hornillos, R. A. Dupke, C. Mendes de Oliveira, M. Moles, L. Sodre Jr, K. Taylor
Summary: The white dwarf population in miniJPAS was analyzed using data from the Javalambre Physics of the accelerating Universe Astrophysical Survey (J-PAS). The results indicate that J-PAS photometry can provide precise effective temperatures and atmospheric compositions for white dwarfs, which are close to those obtained from spectroscopy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
P. T. Rahna, Z-Y Zheng, A. L. Chies-Santos, Z. Cai, D. Spinoso, I Marquez, R. Overzier, L. R. Abramo, S. Bonoli, C. Kehrig, L. A. Diaz-Garcia, M. Povic, R. Soria, J. M. Diego, T. Broadhurst, R. M. Gonzalez Delgado, J. Alcaniz, N. Benitez, S. Carneiro, A. J. Cenarro, D. Cristobal-Hornillos, R. A. Dupke, A. Ederoclite, A. Hernan-Caballero, C. Lopez-Sanjuan, A. Marin-Franch, C. Mendes de Oliveira, M. Moles, L. Sodre, K. Taylor, J. Varela, H. Vazquez Ramio
Summary: This study reports the discovery of double-core Lyman alpha morphology around two high redshift quasi-stellar objects (QSOs) using miniJPAS survey data. The QSOs exhibit extended Lyman alpha and other spectral line morphologies, making them potential candidates for enormous Lyman alpha nebulae.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
J. Laur, E. Tempel, A. Tamm, R. Kipper, L. J. Liivamagi, A. Hernan-Caballero, M. M. Muru, J. Chaves-Montero, L. A. Diaz-Garcia, S. Turner, T. Tuvikene, C. Queiroz, C. R. Bom, J. A. Fernandez-Ontiveros, R. M. Gonzalez Delgado, T. Civera, R. Abramo, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, J. Cenarro, D. Cristobal-Hornillos, R. Dupke, A. Ederoclite, C. Lopez-Sanjuan, A. Marin-Franch, C. M. de Oliveira, M. Moles, L. Sodre, K. Taylor, J. Varela, H. Ramio
Summary: The importance of photometric galaxy redshift estimation is increasing with the development of observational facilities. In this study, a new photometric redshift estimation workflow (TOPz) is developed and tested on miniJPAS survey data. The results show that TOPz achieves the expected redshift accuracy for the upcoming large-scale survey J-PAS and limiting the number of spectra in the template set can further improve the accuracy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Hernan-Caballero, C. N. A. Willmer, J. Varela, C. Lopez-Sanjuan, A. Marin-Franch, H. Vazquez Ramio, T. Civera, A. Ederoclite, D. Muniesa, J. Cenarro, S. Bonoli, R. Dupke, J. Lim, J. Chaves-Montero, J. Laur, C. Hernandez-Monteagudo, J. A. Fernandez-Ontiveros, A. Fernandez-Soto, L. A. Diaz-Garcia, R. M. Gonzalez Delgado, C. Queiroz, J. M. Vilchez, R. Abramo, J. Alcaniz, N. Benitez, S. Carneiro, D. Cristobal-Hornillos, C. Mendes de Oliveira, M. Moles, L. Sodre Jr, K. Taylor
Summary: The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is an astronomical observation project that uses the Javalambre Survey Telescope (JST) and 56 narrow-band filters to observe approximately one-third of the northern sky. Two small surveys, J-NEP and miniJPAS, were conducted to demonstrate the scientific potential and test a new method for the calibration of photometry. The results show that J-NEP has significantly improved performance in terms of depth compared to miniJPAS.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
I. E. Lopez, M. Brusa, S. Bonoli, F. Shankar, N. Acharya, B. Laloux, K. Dolag, A. Georgakakis, A. Lapi, C. Ramos Almeida, M. Salvato, J. Chaves-Montero, P. Coelho, L. A. Diaz-Garcia, J. A. Fernandez-Ontiveros, A. Hernan-Caballero, R. M. Gonzalez Delgado, I. Marquez, M. Povic, R. Soria, C. Queiroz, P. T. Rahna, R. Abramo, J. Alcaniz, N. Benitez, S. Carneiro, J. Cenarro, D. Cristobal-Hornillos, R. Dupke, A. Ederoclite, C. Lopez-Sanjuan, A. Marin-Franch, C. Mendes de Oliveira, M. Moles, L. Sodre Jr, K. Taylor, J. Varela, H. V. Ramio
Summary: Studies show evidence of a scaling relation between supermassive black hole mass (M-BH) and the stellar mass of host galaxies (M-?) in the local Universe, as well as similar evolutions of their differential terms (SFR and BHAR) across cosmic times. However, the understanding of this coevolution is still limited.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Physics, Multidisciplinary
S. Carneiro, F. C. Sobrinho
Summary: It is suggested that the precession of the boosted neutrino magnetic moments in the external magnetic field may explain the tension between the muon anomalous g-factor measured in the Muon g - 2 experiments and the theoretical value predicted by the Standard Model. As the neutrinos and positron resulting from the muon decay are entangled prior to the positron detection, the interaction of the neutrino dipoles with the magnetic field gives origin to an uncertainty in the time modulation of the positron angular distribution. The translated uncertainty in the muon g-factor, delta a(mu) approximate to (1.96 +/- 0.68) ppm, presents 1 sigma agreement with the anomaly measured at Fermilab, delta a(mu) approximate to (2.14 +/- 0.50) ppm. A dependence of the anomaly on the positron energy is also predicted and can be experimentally verified. A fitting of the Brookhaven binned data suggests such a dependence, with chi(2)(r) = 0.86, better than with an energy-independent anomaly, which gives chi(2)(r) = 0.78.
BRAZILIAN JOURNAL OF PHYSICS
(2023)
Article
Astronomy & Astrophysics
F. C. Sobrinho, H. A. Borges, I. P. R. Baranov, S. Carneiro
Summary: Effective models of quantum black holes inspired by LQG successfully replace the classical singularity with a hypersurface of transition and have been able to describe Schwarzschild black holes as well as Planck scale black holes. The quantization method used by Alonso-Bardaji, Brizuela, and Vera preserves the classical form of the angular part of the metric and retains the same horizon area as in the classical theory. The exterior metric generated through a phase rotation shows that the Kretschmann scalar is the same as in the classical Schwarzschild solution, but with a screened central mass due to quantum fluctuations.
CLASSICAL AND QUANTUM GRAVITY
(2023)
Proceedings Paper
Instruments & Instrumentation
A. Marin-Franch, S. Rueda-Teruel, G. Lopez Alegre, C. Iniguez, H. Vazquez Ramio, A. Ederoclite, R. Bello, M. Royo-Navarro, J. M. Casino-Martin, D. Lozano-Perez, E. L. Molina-Ibanez, F. Rueda-Teruel, A. Yanes-Diaz, A. del Pino, C. Lopez-Sanjuan, A. J. Cenarro, D. Cristobal-Hornillos, A. Hernan-Caballero, M. Moles, J. Varela, S. Bielsa de Toledo, S. Chueca, M. Domingez-Martinez, D. Garces-Cubel, N. Martinez-Olivar, J. Munoz-Maudos, H. Rueda-Asensio, I. Soriano-Laguia, J. Castillo, T. Civera, J. Hernandez-Fuertes, A. Lopez-Sainz, A. Moreno-Signes, D. Muniesa-Gallardo, K. Taylor, F. Santoro, J. Cepa, C. Fermino, M. Bastable, G. Haddow, I. Palmer, C. Simpson, A. Spatola, H. Sweeney, C. Tatard, M. Watkins, U. Brauneck, J. M. Casalta, R. Abramo, J. Alcaniz, N. Benitez, S. Bonoli, S. Carneiro, R. Dupke, C. Mendes de Oliveira, L. Sodre, J. Vilchez
Summary: This paper presents the commissioning results, on-sky performance, and first operations of the Javalambre Panoramic Camera (JPCam). The JPCam is a high-resolution camera designed for the J-PAS project, which aims to conduct a photometric survey of a large portion of the northern sky. The camera's large field-of-view and wide wavelength coverage make it ideal for studying cosmology and galaxy formation and evolution.
GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY IX
(2022)
