اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدThe pasta phase within density dependent hadronic models
183
0
0.0
(
0
)
تأليف
S. S. Avancini
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
In the present paper we investigate the onset of the pasta phase with different parametrisations of the density dependent hadronic model and compare the results with one of the usual parametrisation of the non-linear Walecka model. The influence of the scalar-isovector virtual delta meson is shown. At zero temperature two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature only the coexistence phases method is used. npe matter with fixed proton fractions and in beta-equilibrium are studied. We compare our results with restrictions imposed on the the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations.
قيم البحث
اقرأ أيضاً
In this work the low density regions of nuclear and neutron star matter are studied. The search for the existence of pasta phases in this region is performed within the context of the quark-meson coupling (QMC) model, which incorporates quark degrees
of freedom. Fixed proton fractions are considered, as well as nuclear matter in beta equilibrium at zero temperature. We discuss the recent attempts to better understand the surface energy in the coexistence phases regime and we present results that show the existence of the pasta phases subject to some choices of the surface energy coefficient. We also analyze the influence of the nuclear pasta on some neutron star properties. The equation of state containing the pasta phase will be part of a complete grid for future use in supernova simulations.
We have investigated under which conditions hyperons (particularly $Lambda$s and $Sigma^-$s) can be found in the pasta phase. The larger the density and the temperature and the smaller the electron fraction the higher the probability that these parti
cles appear but always in very small amounts. $Lambda$-hyperons only occur in the gas and in smaller amounts than would occur if matter were homogeneous, never with abundancies above 10$^{-5}$. The amount of $Sigma^-$ in the gas is at least two orders of magnitude smaller and can be disregarded in practical calculations.
Baryonic matter close to the saturation density is very likely to present complex inhomogeneous structures collectively known under the name of pasta phase. At finite temperature, the different geometric structures are expected to coexist, with poten
tial consequences on the neutron star crust conductivity and neutrino transport in supernova matter. In the framework of a statistical multi-component approach, we calculate the composition of matter in the pasta phase considering density, proton fraction, and geometry fluctuations. Using a realistic energy functional from relativistic mean field theory and a temperature and isospin dependent surface tension fitted from Thomas-Fermi calculations, we show that different geometries can coexist in a large fraction of the pasta phase, down to temperatures of the order of the crystallization temperature of the neutron star crust. Quantitative estimates of the charge fluctuations are given.
We discuss properties of the method based on time dependent superfluid local density approximation (TDSLDA) within an application to induced fission of 240Pu and surrounding nuclei. Various issues related to accuracy of time evolution and the determi
nation of the properties of fission fragments are discussed.
We study the equilibration and relaxation processes within the time-dependent Hartree-Fock approach using the Wigner distribution function. On the technical side we present a geometrically unrestricted framework which allows us to calculate the full
six-dimensional Wigner distribution function. With the removal of geometrical constraints, we are now able to extend our previous phase-space analysis of heavy-ion collisions in the reaction plane to unrestricted mean-field simulations of nuclear matter on a three-dimensional Cartesian lattice. From the physical point of view we provide a quantitative analysis on the stopping power in TDHF. This is linked to the effect of transparency. For the medium-heavy $^{40}$Ca+$^{40}$Ca system we examine the impact of different parametrizations of the Skyrme force, energy-dependence, and the significance of extra time-odd terms in the Skyrme functional. For the first time, transparency in TDHF is observed for a heavy system, $^{24}$Mg+$^{208}$Pb.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
