In the present work, we study the phase diagram in the $T$−$\mu_{B}$ plane, in the frame of a non-local NJL model with a Gaussian form factor that depends on the spatial components of the momentum (3D-FF), which is fitted to lattice QCD results in the Coulomb gauge. We considered two light quark flavors, diquarks, and vector interactions. Hybrid EOS are obtained by a Maxwell construction of...
Bayesian parameter estimation has been widely used in scientific data processing or model fitting, especially in the field of astronomical research nowdays. There have benn several Python packages (e.g., emcee, PyMC3, etc.) available on PyPI. In this paper the statistics theory of Bayesian parameter estimation and the MCMC (Markov Chain Monte Carlo) sampling algorithm is displayed in a...
In this work we mainly investigated the accretion and jet process near the black-hole horizion of 3C 84 through the high-spatial resolution, multi-waveband data and Faraday rotation measure (RM). Through the multi-waveband spectral energy distribution (SED) of 3C 84, we find that the SED is difficult to fit with pure advection dominated accretion flow (ADAF) or pure jet model. We used a...
A preferred frame S V with minimal speed associeted as a critical speed of superfluid and acoustical causal structure. The gravitational vacuum as superfluid Abstract. We studied a preferred-frame proposal generated from the introduction of a minimum speed in lorentz transformations. We motivate the deformation of Lorentz's transformations , building a geodesic compatible with the existence of...
We construct the physically admissible charged compact star models threaded with anisotropic matter contents via gravitational decoupling approach. Durgapal IV solution containing charge is considered as seed solution for applying minimal geometric deformation approach.We extend the isotropic seed solution into anisotropic domain by imposing suitable mimic constraints on the physical variables...
Cosmic rays have become a very valuable tool in astronomy, as they provide a very different picture of the sky. During the past decades a large number of active astrophysical objects in our Galaxy and beyond have discovered with gamma-ray telescopes. Ground based telescopes are designed to detect the Cherenkov light of the air shower produced when a 0.1–100 TeV photon enters the atmosphere....
The formation of circumstellar discs (CSDs) around the first generation (Population III) stars is an important phenomenon to understand the characteristics of CSDs in the early universe. In the primordial gas environment, cooling is essential to first form the protostars which subsequently can develop disc structure around them. This may lead to disc fragmentation, which can influence the...
We present a relativistic density functional approach to color superconducting quark matter that mimics quark con nement by a fast growth of the quasiparticle self-energy in the con ning region
[1]. The approach is shown to be equivalent to a chiral model of quark matter with medium dependent couplings. The approach to the conformal limit at asymptotically high densities is provided by a...
Gamma-Ray Bursts constitute one of the most fascinating and relevant phenomena in modern science, with strong implications for several fields of astrophysics, cosmology and fundamental physics. Indeed, the huge luminosity, the redshift distribution extending at least up to z~10 and the association with the explosive death of very massive stars make long GRBs (i.e., those lasting up to a few...
With the relativistic generalized noncommutative Heisenberg algebra accommodating gravitational fields and emerging a minimal measurable length uncertainty and with the generalization of the four-dimensional pseudo-Riemann manifold, the fundamental tensor straightforwardly becomes modified. As this appears conformal, we compare it with Weyl's conformal theory. By constructing the Levi-Civita...
László Jenkovszky
Bogolyubov ITP, Kiev, Ukraine
An equation of state (EoS) of the hot and dense nuclear matter is derived from the S-matrix formulation of statistical mechanics and observed high-energy hadron scattering data. The EoS shows a local minimum with negative temperature (super-cooling) with observable effects in astrophysics and/or heavy ion collisions.
In this brief report, we approach the singularity, flatness, homogeneity and horizon problems from the classical point of view of the branch-cut cosmology.
The exclusive photo- and electroproduction of the light vector mesons $\rho, \, \omega \, \text{and } \phi$ are studied within the color dipole picture as function of the center-of-mass energy of the $\gamma p$ collision and the momentum transfer squared $|t|$. The corresponding vector meson wave functions have been computed with the relativistic AdS/QCD holographic approach. This enabled us...
In this talk I will demonstrate how we can use machine learning based computational paradigm to help our exploration of QCD matter in extreme conditions. The focus is about properties of hot and dense nuclear matter related studies. Around it, experimentally the relativistic nuclear collision are performed to realize the extreme conditions for studying it while theoretically the...
In this talk the gravitational theory known as Unimodular Gravity is reviewed. In particular, a cosmological model is built and compared with the standard LCDM model. Once the dynamics of a homogeneous and isotropic universe is analyzed, cosmological perturbations are studied. These, unlike what has been reported in the literature so far, do present distinctions typical of the theory due to...
We study the effects of magnetic fields on gravitational wave signals emitted from isolated quark stars due to deformation caused by the strong magnetic field. For this purpose we construct a toy model in order to make estimates of the order of magnitude of the magnetic field that will cause sufficient deformation in a quark star for the detection of gravitational waves.
The dependence of partons on the constitution of proton spin remains an interesting and persistent problem in hadron physics, but one that should be widely addressed by future colliders with polarized beams, such as the Electron-Ion Collider (EIC). Quark helicity contributions and spin-dependent parton distribution functions (hPDFs) can be calculated using the Kovchegov-Pitonyak-Sievert (KPS)...
We study the behavior highly magnetized two light flavors quark matter
in the frame of a non-local NJL-type model including the coupling of fermions
to the Polyakov loop.
We considered a Gaussian "instantaneous" form factor that depends on the spacial components
of the momentum (3DFF). We show the phase diagrams in the $T-\mu$ plane for different
strengths of the magnetic field. We...
Magnetars are strong magnetized neutron stars endowed with surface magnetic fields of the order of $10^{14}-10^{15}$ G, and with presumably much stronger fields in their interior. They could emit quiescent X-ray, repeating burst of soft gamma ray, and even the giant flares. We investigate the effects of a strong magnetic
field $B$ on the anisotropy of pressure of magnetars using a...
In this work we study the photoproduction of ρ mesons considering the proton and the nucleus as the target. Utilizing the dipole picture and the wave functions obtained via AdS/QCD, we were able to describe the HERA ρp data and extend the formalism to the nuclear case considering the Glauber-Gribov model. The preliminary results obtained in the nuclear regime are compared to the recent LHC...
I will briefly discuss how the first images of the supermassive black holes M87 and Sgr A were obtained by the EHT collaboration. In particular, I will describe the theoretical aspects that have allowed us to model the dynamics of the plasma accreting onto the black hole and how such dynamics was used to generate synthetic black-hole images. I will also illustrate how the comparison between...
We study the classical Friedman equations for the time-varying cosmological term $\tilde\Lambda$
and Hubble function $H$, together with quantised field equations for the production of massive $M\gg H$ particles, namely, the $\tilde\Lambda$CDM scenario of dark energy and matter interactions. Classical slow components ${\mathcal O}(H^{-1})$ are separated from quantum fast components ${\mathcal...
Neutron stars are the most mysterious objects in the universe, with a radius of the order of 10 km and masses that can reach two solar masses. In 2017, a gravitational wave was detected (GW170817) and its source was identified as the merger of two neutron stars. Later on, a mass-gap object (either a neutron star or a black hole) was identified in the GW190814 event. To understand neutron...
The purpose of this talk is to illuminate the advantages of the manifestly covariant formulation of canonical gauge gravity. The framework of the De Donder-Weyl Hamiltonian field theory and of canonical transformations is introduced. We sketch how the Canonical Covariant Gauge theory of Gravity (CCGG) is derived from a few basic physical and mathematical assumptions. Some novel implications...
The lattice QCD simulations predict a slow cross-over from parton to hadron matter, especially at small baryon densities. When attempting to apply this to the early universe, we find that the latest non-leptonic phase transition would not account for the large-scale structure of the universe. In the early epochs of the evolution of the universe, it is conjectured that the baryonic density,...
The spin evolution of Rotation-Powered Pulsars is well known and used to estimate ages and surface magnetic fields of old pulsars. Due the energy loss by radiation allows the pulsar to undergo a systematic spin-down from an initial spin period, then, the deceleration of the pulsar is given by an empirical formula obtained by balancing the spin-down luminosity with the energy loss by radiation...
The Cas A structure and spectral features obtained with the multiwavelength observations have clear signs of young SNRs, which are expected to be a shell formed with the explosion blast wave moving into the circumstellar medium with magnetic fields, as well as another one due to the decelerating and compressing the outflowing ejecta. In observations in radio and X-rays, both features were...
The most massive structures of the Universe formed at the knots of the cosmic web at high redshifts and constitute the present-day clusters of galaxies. They are dense, gravitationally bound, nearly virialized systems of galaxies. The early stages of these structures are called protoclusters and they are the natural laboratories to observe the role of environmental effects on galaxy evolution....
In the framework of Thomas-Fermi approximation, we study systematically the EOSs and microscopic structures of neutron star matter in a vast density range with nb ≈ 10-10 -2 fm-3, where various covariant density functionals are adopted, i.e., those with nonlinear self couplings (NL3, PK1, TM1, GM1, MTVTC) and density-dependent couplings (DD-LZ1, DDME-X, PKDD, DD-ME2, DD2, TW99). Six types of...
Using the quadratic expansion in the photon fields of Euler-Heisenberg (EH) non-linear electrodynamics (NLED) Lagrangian model we study relevant vacuum properties in a scenario involving the propagation of a photon probe in the presence of a background constant and static magnetic field, ${\bf B_e}$.We compute the gauge invariant, symmetric and conserved energy-momentum tensor (EMT) and the...
The present research aimed to describe macroscopic properties of neutron stars assuming zero temperature and different nuclear models, such as the (linear) QHD – I and the non-linear Walecka model. The first one considers that the interaction inside the nucleus has two contributions: an attractive one at large distances, and a repulsive one at short distances. Adding to that, the second model...
A recently developed variational resummation technique, incorporating renormalization group properties consistently, has been shown to solve the scale dependence problem that plagues the evaluation of thermodynamical quantities, e.g., within the framework of approximations such as in the hard-thermal-loop resummed perturbation theory. This method is used in the present work to evaluate...
Fast radio bursts (FRBs) are millisecond-duration radio flashes with extremely high bright temperatures, but the origin is still unknown since the discovery in 2007 though this research field witnessed a rapid growth in the frontiers both observational and theoretical. We propose that coherent curvature radiation by bunches (maybe triggered by starquakes) in a magnetosphere of neutron star to...
In this work, we solve the structure formation in the Universe for the scalar field model as dark matter in its hydrodynamic approximation, and for this, we implement the model in the MG-PICOLA code, which uses the COLA method, which allows solving the model with a lower computational cost but with a reduction in resolution compared to other methods such as N-body simulations. We perform...
Event timing and star lore can be used to identify associated asterisms both in Mesoamerica and the American Southwest. The findings are given greater weight due to correlations between the two areas. This presentation will focus on Tezcatlipoca, Quetzalcoatl, Tlaloc, and Chalchiuhtlicue, along with their counterparts at Hopi.
Depending on the dynamics of a binary neutron star merger, the collision may result in a differentially rotating compact object. Differentially rotating stars can sustain a total mass considerably higher than that of a uniformly rotating star, giving rise to “hypermassive” objects like hypermassive neutron stars. These stars are likely to exhibit extreme structural deformation along the radial...
The radio-loud active galactic nuclei having the radio emission arising from a core region rather than from lobes are often referred to as "blazars" and include Flat Spectrum Radio Quasars (FSRQ) and BL Lacertae (BL Lac) objects. The extragalactic source of radio emission source 3C454.3 is a well-known flat-spectrum radio quasar (FSRQ) at redshift z = 0.859. It has shown remarkably high...
We study the surface tension and the curvature energy of three-flavor cold quark matter in equilibrium under weak interactions within the Nambu-Jona-Lasinio model including vector interactions. We consider both cases of local and global electric charge neutrality.
In order to describe finite size effects we use the multiple reflection expansion (MRE) framework, and show our results for...
In 2015 the first detection of gravitational waves was made, such detection was made by kilometer size interferometer detectors. The calibration of such a detector is still a challenge then a calibrator was proposed. This calibrator is a resonant mass gravitational wave detector that operates at frequencies where the gravitational waves have been detected. Previou work showed that a...
Precise experiments yielded results significantly discordant with the predictions of the standard model; among them, the beautiful decays and the value of the anomalous magnetic moment of the muon. I will make a brief exposition of these problems as well as review the solution of a vector leptoquark which, by virtue of explaining many of the disagreements with the SM, is increasingly gaining...
Magnetars are a type of pulsars powered by magnetic field energy. Part of X-ray luminosities of magnetars in quiescence have a thermal origin and can be fitted by a blackbody spectrum with temperature kT $\sim$ 0.2－0.6 keV, much higher than the typical values for the rotation-powered pulsars. The observation and theoretical study of magnetar are one of hot topics in the field of pulsar...
The inclination angle $\chi$ between the magnetic and rotation axes of pulsars is an important physical parameter, whose change would lead to observable effects, such as varitions in the pulse beam width and braking index of the star. In this paper, we first give a comparison between the vacuum model and the plasma-filled model, then investigate the magnetic inclination angle change rates for...
In this work the cosmological dynamics of two scalar dark matter fields are analyzed, using different potentials and masses. The purpose is to constrain the relationship between the energy densities that each axion contributes to, as well as to estimate the range of masses that these fields can have. We use " the area criterion" and the Monte Python code using estimated data from Lyman-alpha...
The recent observation of the object HESS J1731-347 by Doroshenko et al. (2022) suggests the existence of a very light and very compact neutron star.
In order to quantify this result, the authors of this study consider a family of chiral equation of state (EOS) models that can reproduce the properties of the aforementioned object as well as to fulfill state-of-the-art compact stars...
Cygnus Region contains many objects that are bright in all wavelengths, including one of the most powerful active star formation regions as well as pulsars, and supernova remnants. One of them is γCygni SNR shell-type supernova remnant which is considered a middle-aged SNR. γCygni SNR has been intensively studied through multi-wavelength observations in radio, X-rays, and MeV-TeV energy ranges...
