Simulations of cold nuclear matter at sub-saturation densities

Molinelli, P. A. Giménez; Nichols, J. I.; López, Jörge A.; Dorso, C. O.

doi:10.1016/j.nuclphysa.2014.01.003

Cited by 25 publications

(17 citation statements)

References 44 publications

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“…In the classical molecular dynamics (CMD) approach (Dorso, Molinelli, and Lopez, 2011;Horowitz et al, 2011;Dorso, Giménez Molinelli, Nichols, and Lopez, 2012;Piekarewicz and Toledo Sanchez, 2012;Schneider et al, 2013;Giménez Molinelli et al, 2014;Giménez Molinelli and Dorso, 2015), a certain number of nucleons is placed inside a box of given volume to reproduce a fixed density. The velocities of the particles are chosen to represent a Maxwellian distribution at given temperature.…”

Section: Nucleons-in-cell Calculationsmentioning

confidence: 99%

Equations of state for supernovae and compact stars

et al. 2017

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A review is given of various theoretical approaches for the equation of state (EoS) of dense matter, relevant for the description of core-collapse supernovae, compact stars, and compact star mergers. The emphasis is put on models that are applicable to all of these scenarios. Such EoS models have to cover large ranges in baryon number density, temperature, and isospin asymmetry. The characteristics of matter change dramatically within these ranges, from a mixture of nucleons, nuclei, and electrons to uniform, strongly interacting matter containing nucleons, and possibly other particles such as hyperons or quarks. As the development of an EoS requires joint efforts from many directions, different theoretical approaches are considered and relevant experimental and observational constraints which provide insights for future research are discussed. Finally, results from applications of the discussed EoS models are summarized.

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Section: Nucleons-in-cell Calculationsmentioning

confidence: 99%

Equations of state for supernovae and compact stars

et al. 2017

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“…It is known that the imposed boundary conditions have an impact on the structures due to symmetry violation and possibly spatial mismatch [29,30]. A study within classical molecular dynamics without Coulomb interactions implies that this may be particularly critical for extended, inhomogeneous structures [31]. However, the numerical expense of fully quantum-dynamical simulations sets limits on the affordable box sizes.…”

Section: Simulation and Basic Quantitiesmentioning

confidence: 99%

Nuclear “pasta matter” for different proton fractions

et al. 2014

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Nuclear matter under astrophysical conditions is explored with time-dependent and static Hartree-Fock calculations. The focus is in a regime of densities where matter segregates into liquid and gaseous phases unfolding a rich scenario of geometries, often called nuclear pasta shapes (e.g., spaghetti, lasagna). Particularly the appearance of the different phases depending on the proton fraction and the transition to uniform matter are investigated. In this context the neutron background density is of special interest, because it plays a crucial role in the type of pasta shape that is built. The study is performed in two dynamical ranges, once for hot matter and once at temperature zero, to investigate the effect of cooling.

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“…Since only periodic geometries that fit into the unit cell can be explored, the simulation space must be sufficiently large to contain at least one unit cell of the pasta structure. Even if this condition is fulfilled, finite size effects such as dependence on the geometry of the simulation space [47] and numerical shell effects [28] may appear. As a result, the simulation volume needs to be maximized to ensure that finite size effects are minimal.…”

Section: Introductionmentioning

confidence: 99%

Quantum nuclear pasta and nuclear symmetry energy

2017

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Complex and exotic nuclear geometries are expected to appear naturally in dense nuclear matter found in the crust of neutron stars and supernovae environment collectively referred to as "nuclear pasta". The pasta geometries depend on the average baryon density, proton fraction and temperature and are critically important in the determination of many transport properties of matter in supernovae and the crust of neutron stars. Using a set of self-consistent microscopic nuclear energy density functionals we present the first results of large scale quantum simulations of pasta phases at baryon densities 0.03 ≤ ρ ≤ 0.10 fm −3 , proton fractions 0.05 ≤ Yp ≤ 0.40, and zero temperature. The full quantum simulations, in particular, allow us to thoroughly investigate the role and impact of the nuclear symmetry energy on pasta configurations. We use the Sky3D code that solves the Skyrme Hartree-Fock equations on a three-dimensional Cartesian grid. For the nuclear interaction we use the state of the art UNEDF1 parametrization, which was introduced to study largely deformed nuclei, hence is suitable for studies of the nuclear pasta. Density dependence of the nuclear symmetry energy is simulated by tuning two purely isovector observables that are insensitive to the current available experimental data. We find that a minimum total number of nucleons A = 2000 is necessary to prevent the results from containing spurious shell effects and to minimize finite size effects. We find that a variety of nuclear pasta geometries are present in the neutron star crust and the result strongly depends on the nuclear symmetry energy. The impact of the nuclear symmetry energy is less pronounced as the proton fractions increase. Quantum nuclear pasta calculations at T = 0 MeV are shown to get easily trapped in meta-stable states, and possible remedies to avoid meta-stable solutions are discussed.

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Simulations of cold nuclear matter at sub-saturation densities

Cited by 25 publications

References 44 publications

Equations of state for supernovae and compact stars

Equations of state for supernovae and compact stars

Nuclear “pasta matter” for different proton fractions

Quantum nuclear pasta and nuclear symmetry energy

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