The Critical Exponent of Nuclear Fragmentation

Barrañón, Armando; Cárdenas, Rolando; Dorso, C. O.; Lopez, J. A Rodriguez

doi:10.1556/aph.17.2003.1.8

Cited by 21 publications

(19 citation statements)

References 24 publications

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“…Such potential mimics infinite systems with realistic binding energy, density and compressibility and to produce heavy-ion dynamics comparable to those predicted by the Vlasov-Nordheim equation. This parameter-free model has been successfully used to study nuclear reactions obtaining mass multiplicities, momenta, excitation energies, secondary decay yields, critical phenomena and isoscaling behavior that have been compared to experimental data [26,[67][68][69][70][71][72][73][74][75]. More recently, and of interest to the present work, the model was used to study infinite nuclear systems at low temperatures [41] and in neutron star crust environments, including the pasta structures that form in NM and NSM [10,18,19,21,32,51].…”

Section: A Classical Molecular Dynamicsmentioning

confidence: 99%

Properties of nuclear pastas

2020

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In this Review we study the nuclear pastas as they are expected to be formed in neutron star cores. We start with a study of the pastas formed in nuclear matter (composed of protons and neutrons), we follow with the role of the electron gas on the formation of pastas, and we then investigate the pastas in neutron star matter (nuclear matter embedded in an electron gas). Nuclear matter (NM) at intermediate temperatures (1 MeVT 15 MeV), at saturation and sub-saturation densities, and with proton content ranging from 30% to 50% was found to have liquid, gaseous and liquid-gas mixed phases. The isospin-dependent phase diagram was obtained along with the critical points, and the symmetry energy was calculated and compared to experimental data and other theories. At low temperatures (T 1 MeV) NM produces crystal-like structures around saturation densities, and pasta-like structures at sub-saturation densities. Properties of the pasta structures were studied with cluster-recognition algorithms, caloric curve, the radial distribution function, the Lindemann coefficient, Kolmogorov statistics, Minkowski functionals; the symmetry energy of the pasta showed a connection with its morphology.Neutron star matter (NSM) is nuclear matter embedded in an electron gas. The electron gas is included in the calculation by the inclusion of an screened Coulomb potential. To connect the NM pastas with those in neutron star matter (NSM), the role the strength and screening length of the Coulomb interaction have on the formation of the pastas in NM was investigated. Past was found to exist even without the presence of the electron gas, but the effect of the Coulomb interaction is to form more defined pasta structures, among other effects. Likewise, it was determined that there is a minimal screening length for the developed structures to be independent of the cell size.Neutron star matter was found to have similar phases as NM, phase transitions, symmetry energy, structure function and thermal conductivity. Like in NM, pasta forms at around T ≈ 1.5 MeV, and liquid-to-solid phase changes were detected at T ≈ 0.5 MeV. The structure function and the symmetry energy were also found to depend on the pasta structures. Contents I. IntroductionA. The pasta B. The pasta in nuclear matter and in neutron star matter II. Nuclear matter A. Nuclear matter at intermediate temperatures B. Nuclear matter at low temperatures C. Summary of nuclear matter properties III. Electron gas: connecting nuclear matter with neutron star matter A. The strength of V C B. The screening length C. Summarizing the electron gas IV. Neutron star matter A. Symmetric neutron star matter B. Non-symmetric neutron star matter C. The symmetry energy D. Neutrino transport properties E. Properties of non-traditional pasta F. The nucleon thermal conductivity G. Summary of NSM properties V. Conclusion A. Nuclear matter B. The electron gas C. The pasta in neutron star matter VI. Appendices A. Classical Molecular Dynamics B. The Maxwell construction C. Nuclear symmetry energy from CMD at...

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Section: A Classical Molecular Dynamicsmentioning

confidence: 99%

Properties of nuclear pastas

2020

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“…This parameter-free model has been successfully used to study nuclear reactions obtaining mass multiplicities, momenta, excitation energies, secondary decay yields, critical phenomena and isoscaling behavior that have been compared to experimental data [48][49][50][51][52][53][54][55][56][57]. More recently, and of interest to the present work, the model was used to study infinite nuclear systems at low temperatures [58] and in neutron star crust environments [45][46][47].…”

Section: Classical Molecular Dynamicsmentioning

confidence: 99%

Isospin-asymmetric nuclear matter

et al. 2014

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This study uses classical molecular dynamics to simulate infinite nuclear matter and study the effect of isospin asymmetry on bulk properties such as energy per nucleon, pressure, saturation density, compressibility and symmetry energy. The simulations are performed on systems embedded in periodic boundary conditions with densities and temperatures in the ranges ρ = 0.02 to 0.2 f m −3 and T = 1, 2, 3, 4 and 5 MeV, and with isospin content of x = Z/A = 0.3, 0.4 and 0.5. The results indicate that symmetric and asymmetric matter are self-bound at some temperatures and exhibit phase transitions from a liquid phase to a liquid-gas mixture. The main effect of isospin asymmetry is found to be a reduction of the equilibrium densities, a softening of the compressibility and a disappearance of the liquid-gas phase transition. A procedure leading to the evaluation of the symmetry energy and its variation with the temperature was devised, implemented and compared to mean field theory results.

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“…In the present work, we use a molecular dynamics (M D) model that can describe non-equilibrium dynamics, hydrodynamic flow and changes of phase without adjustable parameters. The combination of this M D code with a fragment-recognition algorithm, has been dubbed "Latino" [15], and in recent years it has been applied successfully to study, among other things, neck fragmentation [16], phase transitions [17], critical phenomena [18,19] and the caloric curve [20,21] in nuclear reactions.…”

Section: Molecular Dynamicsmentioning

confidence: 99%

Dynamical aspects of isoscaling

et al. 2006

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The origin and dynamical evolution of isoscaling was studied using classical molecular dynamics simulations of ${}^{40}$Ca + ${}^{40}$Ca, ${}^{48}$Ca + ${}^{48}$Ca, and ${}^{52}$Ca + ${}^{52}$Ca, at beam energies ranging from $20 \ MeV/A$ to $85 MeV/A$. The analysis included a study of the time evolution of this effect. Isoscaling was observed to exist in these reactions from the very early primary isotope distributions (produced by highly {\it non-equilibrated} systems) all the way to asymptotic times. This indicates that isoscaling is independent of quantum effects and thermodynamical equilibrium. In summary, collision-produced isoscaling appears to be due more to the mere partitioning of the proton-neutron content of the participant nuclei, than to specific details of the reaction dynamics

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The Critical Exponent of Nuclear Fragmentation

Cited by 21 publications

References 24 publications

Properties of nuclear pastas

Properties of nuclear pastas

Isospin-asymmetric nuclear matter

Dynamical aspects of isoscaling

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