Preliminary EoS for core-collapse supernova simulations with the QMC model

In this work we present the preliminary results of a complete equation of state (EoS) for core-collapse supernova simulations. We treat uniform matter made of nucleons using the the quark-meson coupling (QMC) model. We show a table with a variety of thermodynamic quantities, which covers the proton fraction range $Y_{p}=0-0.65$ with the linear grid spacing $\Delta Y_{p}=0.01$ ($66$ points) and the density range $\rho_{B}=10^{14}-10^{16}$g.cm$^{-3}$ with the logarithmic grid spacing $\Delta log_{10}(\rho_{B}/[$g.cm$^{-3}])=0.1$ ($21$ points). This preliminary study is performed at zero temperature and our results are compared with the widely used EoS already available in the literature

Electrolytes between dielectric charged surfaces: Simulations and theory

We present a simulation method to study electrolyte solutions in a dielectric slab geometry using a modified 3D Ewald summation. The method is fast and easy to implement, allowing us to rapidly resum an infinite series of image charges. In the weak coupling limit, we also develop a mean-field theory which allows us to predict the ionic distribution between the dielectric charged plates. The agreement between both approaches, theoretical and simulational, is very good, validating both methods. Examples of ionic density profiles in the strong electrostatic coupling limit are also presented. Finally, we explore the confinement of charge asymmetric electrolytes between neutral surfaces

Distribution-Based Categorization of Classifier Transfer Learning

Transfer Learning (TL) aims to transfer knowledge acquired in one problem, the source problem, onto another problem, the target problem, dispensing with the bottom-up construction of the target model. Due to its relevance, TL has gained significant interest in the Machine Learning community since it paves the way to devise intelligent learning models that can easily be tailored to many different applications. As it is natural in a fast evolving area, a wide variety of TL methods, settings and nomenclature have been proposed so far. However, a wide range of works have been reporting different names for the same concepts. This concept and terminology mixture contribute however to obscure the TL field, hindering its proper consideration. In this paper we present a review of the literature on the majority of classification TL methods, and also a distribution-based categorization of TL with a common nomenclature suitable to classification problems. Under this perspective three main TL categories are presented, discussed and illustrated with examples

Isospin Constraints on the Parametric Coupling Model for Nuclear Matter

We make use of isospin constraints to study the parametric coupling model and the properties of asymmetric nuclear matter. Besides the usual constraints for nuclear matter - effective nucleon mass and the incompressibility at saturation density - and the neutron star constraints - maximum mass and radius - we have studied the properties related with the symmetry energy. These properties have constrained to a small range the parameters of the model. We have applied our results to study the thermodynamic instabilities in the liquid-gas phase transition as well as the neutron star configurations.Comment: 11 pages, 10 figure

Compact stars within an asy-soft quark-meson-coupling model

We investigate compact star properties within the quark meson coupling model (QMC) with a soft symmetry energy density dependence at large densities. In particular, the hyperon content and the mass/radius curves for the families of stars obtained within the model are discussed. The hyperon-meson couplings are chosen according to experimental values of the hyperon nuclear matter potentials, and possible uncertainties are considered. It is shown that a softer symmetry energy gives rise to stars with less hyperons, smaller radii and larger masses. Hyperon-meson couplings may also have a strong effect on the mass of the star.Comment: 7 pages, revtex, accepted in Phys. Rev.

Scalaroca stars: coupled scalar-Proca solitons

We construct and explore the physical properties of \textit{scalaroca stars}: spherically symmetric solitonic solutions made of a complex scalar field $\Phi$ and a complex Proca field $A^\mu$. We restrict our attention to configurations in which both fields are in the fundamental state and possess an equal mass, focusing on the cases when ($i$) the scalar and Proca fields are (non--linearly) super--imposed and do not interact with each other; and ($ii$) the scalar and Proca fields interact through the term $\alpha |\Phi| ^2 A^\mu A_\mu$. The solutions are found numerically for the non--interacting case ($\alpha=0$) as well as for both signs of the interaction coupling constant $\alpha$. While pure ($i.e.$ single--field) Proca/scalar boson stars are the most/least massive for weakly--interacting fields, one can obtain more massive solutions for a sufficiently strong interaction. Besides, in the latter case, solutions can be either in a synchronized state -- in which both fields have the same frequency -- or in a non--synchronized state. In addition, we observe that the coupling between the two fields allows solitonic solutions with a real scalar field. We further comment on the possibility of spontaneous scalarization and vectorization of the interacting solitonic solution.Comment: 21 pages, 13 figures, this project was started before the recently published work ArXiv:2304.0801

Low density instabilities in asymmetric nuclear matter within QMC with δ\delta-meson

In the present work we include the isovector-scalar $\delta$-meson in the quark-meson coupling model (QMC) and study the properties of asymmetric nuclear within QMC without and with the $\delta$-meson. Recent constraints set by isospin diffusion on the slope parameter of the nuclear symmetry energy at saturation density are used to adjust the model parameters. The thermodynamical spinodal surfaces are obtained and the instability region at subsaturation densities within QMC and QMC$\delta$ models are compared with mean-field relativistic models. The distillation effect in the QMC model is discussed.Comment: 8 pages, 7 captions, 12 figure