10929692
Extension of quantum molecular dynamics and its application to heavy-ion collisions.
In order to treat low-energy heavy-ion reactions, we make an extension of quantum molecular dynamics method. A phenomenological Pauli potential is introduced into effective interactions to approximate the nature of the Fermion many-body system. We treat the widths of nucleon wave-packets as time-dependent dynamical variables. With these modifications, our model can well describe the ground-state properties in wide mass range. Improvements due to the extension are also obtained in the nucleus-nucleus collision calculations.
2937697
Critical phenomena in finite systems
We discuss the dynamics of finite systems within molecular dynamics models. Signatures of a critical behavior are analyzed and compared to experimental data both in nucleus-nucleus and metallic cluster collisions. We suggest the possibility to explore the instability region via tunneling. In this way we can obtain fragments at very low temperatures and densities. We call these fragments quantum drops.
119187846
Hot hadron-quark mixed phase including hyperons
We study the hadron-quark phase transition with the finite-size effects at finite temperature. For the hadron phase, we adopt a realistic equation of state in the framework of the Brueckner-Hartree-Fock theory including hyperons. The properties of the mixed phase are clarified by considering the finite-size effects under the Gibbs conditions. We find that the equation of state becomes softer than that at zero temperature for some density region. We also find that the equation of state gets closer to that given by the Maxwell construction. Moreover, the number of hyperons is suppressed by the presence of quarks. These are characteristic features of the hadron-quark mixed phase, and should be important for many astrophysical phenomena such as mergers of binary neutron stars.
119341714
Quark deconfinement transition in hyperonic matter
Abstract We discuss the properties of the hadron–quark mixed phase in compact stars using a realistic equation of state of hyperonic matter and the MIT bag model. We find that the equation of state of the mixed phase is similar to that given by the Maxwell construction, but that the mixed phase becomes mechanically unstable if the surface tension of the interface between the two pure phases is strong enough. The composition of the mixed phase is very different from that of the Maxwell construction; in particular, hyperons are completely suppressed.
15618191
Charge Screening Effect in the Hadron-Quark Mixed Phase
The Coulomb interaction effect is consistently taken into account in the hadron-quark mixed phase. It is found that the finite-size effects, such as the surface effect and the charge screening effect, greatly alter the properties of the mixed phase and restrict its density region. In particular, the charge screening effect and the rearrangement of the charged particles are elucidated. As the Gibbs conditions are satisfied throughout the numerical procedure, we show that the Maxwell construction becomes physically meaningful and the equation of state becomes similar to that given by the Maxwell construction.
33155232
Simulation of transitions between "pasta" phases in dense matter.
Calculations of equilibrium properties of dense matter predict that at subnuclear densities nuclei can be rodlike or slablike. To investigate whether transitions between phases with nonspherical nuclei can occur during the collapse of a star, we perform quantum molecular dynamic simulations of the compression of dense matter. We have succeeded in simulating the transitions between rodlike and slablike nuclei and between slablike nuclei and cylindrical bubbles. Our results strongly suggest that nonspherical nuclei can be formed in the inner cores of collapsing stars.
16642064
Proton inelastic scattering to continuum studied with antisymmetrized molecular dynamics.
The intermediate energy ({ital p},{ital p}{prime}{ital x}) reaction is studied with antisymmetrized molecular dynamics (AMD) in the cases of {sup 58}Ni target with {ital E}{sub {ital p}}=120 MeV and {sup 12}C target with {ital E}{sub {ital p}}=200 and 90 MeV. Angular distributions for various {ital E}{sub {ital p}{prime}} energies are shown to be reproduced well without any adjustable parameter, which shows the reliability and usefulness of AMD in describing light-ion reactions. Detailed analyses of the calculations are made in the case of {sup 58}Ni target and the following results are obtained: Two-step contributions are found to be dominant in some large angle region and to be indispensable for the reproduction of data. Furthermore, the reproduction of data in the large angle region {theta}{approx_gt}120{degree} for {ital E}{sub {ital p}{prime}}=100 MeV is shown to be due to three-step contributions. Angular distributions for {ital E}{sub {ital p}{prime}}{approx_gt}40 MeV are found to be insensitive to the choice of different in-medium nucleon-nucleon cross sections {sigma}{sub {ital N}{ital N}} and the reason for this insensitivity is discussed in detail. On the other hand, the total reaction cross section and the cross section of evaporated protons are found to be sensitive to {sigma}{sub {ital N}{ital N}}. Inmore » the course of the analyses of the calculations, comparison is made with the distorted wave approach.« less