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Related papers: Simulating bulk viscosity in neutron stars. I. For…

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Many of the currently available equations of state for core-collapse supernova simulations give large neutron star radii and do not provide large enough neutron star masses, both of which are inconsistent with some recent neutron star…

Solar and Stellar Astrophysics · Physics 2015-06-05 Andrew W. Steiner , Matthias Hempel , Tobias Fischer

The 4-dimensionally covariant approach to multiconstituent Newtonian fluid dynamics presented in the preceding article of this series is developed by construction of the relevant 4-dimensional stress energy tensor whose conservation in the…

Astrophysics · Physics 2009-11-10 Brandon Carter , Nicolas Chamel

State-of-the-art fluid dynamical simulations of relativistic heavy-ion collisions employ initial state models which result in a rather strong radial flow. In order to fit the experimental observables, a non-negligible bulk viscosity of the…

Nuclear Theory · Physics 2022-05-12 Josef Bobek , Iurii Karpenko

We present the results of Newtonian hydrodynamic simulations of the coalescence of a binary consisting of a black hole with a neutron star. The calculations show that for a wide range of initial conditions the core of the neutron star…

Astrophysics · Physics 2009-10-30 W. Kluzniak , W. H. Lee

We analyse the implications of superfluid turbulence for neutron star physics. We begin by extending our previous results for the mutual friction force for a straight vortex array to account for the self-induced flow which arises when the…

Astrophysics · Physics 2012-11-16 N. Andersson , T. Sidery , G. L. Comer

We perform 3D hydrodynamical simulations of new-born neutron stars (NSs) colliding with main-sequence binary companions after supernova explosions. Based on those hydrodynamical models, we construct a semi-analytical formula that describes…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Ryosuke Hirai , Philipp Podsiadlowski

A new approach that is a combination of classical thermodynamics and macroscopic kinetics is offered for studying the nucleation kinetics in condensed binary solutions. The theory covers the separation of liquid and solid solutions…

Chemical Physics · Physics 2018-11-14 Nikolay V. Alekseechkin

Magnetic field evolution in neutron star cores is not fully understood. We describe the field evolution both for one barotropic fluid as well as two collisionally coupled barotropic fluids with different density profiles using the anelastic…

High Energy Astrophysical Phenomena · Physics 2025-12-16 Andrei Igoshev , Nicolás A. Moraga , Andreas Reisenegger , Calum S. Skene , Rainer Hollerbach

We present a simple (microscopic) model in which bulk viscosity plays a role in explaining the present acceleration of the universe. The effect of bulk viscosity on the Friedmann equations is to turn the pressure into an "effective"…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-23 Jean-Sebastien Gagnon , Julien Lesgourgues

We investigate the dynamics and evolution of coalescing neutron stars. Although the code (Piecewise Parabolic Method) is purely Newtonian, we do include the emission of gravitational waves and their backreaction on the hydrodynamic flow.…

Astrophysics · Physics 2008-11-26 M. Ruffert , H. -Th. Janka , G. Schaefer

Magnetohydrodynamic (MHD) turbulence in neutron star (NS) merger remnants can impact their evolution and multimessenger signatures, complicating the interpretation of present and future observations. Due to the high Reynolds numbers and the…

High Energy Astrophysical Phenomena · Physics 2020-07-30 David Radice

After an introduction to the QCD phase diagram, the nuclear equations of state, and neutron star mergers, I discuss three projects related to transport and nuclear matter in neutron star mergers. The first is the nature of beta equilibrium…

Nuclear Theory · Physics 2021-11-24 Steven P. Harris

This article starts by providing an introductory overview of the theoretical mechanics of rotating neutron stars as developped to account for the frequency variations, and particularly the discontinuous glitches, observed in pulsars. The…

Astrophysics · Physics 2007-05-23 Brandon Carter

We add an ensemble of nuclei to the equation of state for homogeneous nucleonic matter to generate a new set of models suitable for astrophysical simulations of core-collapse supernovae and neutron star mergers. We implement empirical…

Nuclear Theory · Physics 2022-03-16 Xingfu Du , Andrew W. Steiner , Jeremy W. Holt

We use a high-resolution grid-based hydrodynamics method to simulate the multi-phase interstellar medium in a Milky Way-size quiescent disk galaxy. The models are global and three-dimensional, and include a treatment of star formation and…

Astrophysics · Physics 2009-11-13 Elizabeth J. Tasker , Greg L. Bryan

Solving the kinetic equation for ionization-recombination processes in cold plasmas for temperatures much lower than the first ionization potentials, we derive an explicit expression for the bulk viscosity. We obtain that bulk viscosity can…

Plasma Physics · Physics 2026-03-03 Albert M. Varonov , Todor M. Mishonov

The calculation of transport properties of Fermi liquids, based on the formalism developed by Abrikosov and Khalatnikov, requires the knowledge of the probability of collisions between quasiparticles in the vicinity of the Fermi surface. We…

Nuclear Theory · Physics 2008-11-26 Omar Benhar , Marco Valli

In neutron stars, flavor-changing weak interactions determine the equilibrium fraction of protons over neutrons. In binary neutron-star mergers, violent changes in density modify this equilibrium value at timescales of milliseconds,…

Nuclear Theory · Physics 2024-02-13 Yumu Yang , Mauricio Hippert , Enrico Speranza , Jorge Noronha

Inferring the properties of dense matter is one of the most exciting prospects from the measurement of gravitational waves from neutron star mergers. However, it will require reliable numerical simulations that incorporate viscous…

General Relativity and Quantum Cosmology · Physics 2018-01-31 Mark G. Alford , Luke Bovard , Matthias Hanauske , Luciano Rezzolla , Kai Schwenzer

The properties of high-density nuclear and neutron matter are studied using a relativistic mean-field approximation to the nuclear matter energy functional. Based on ideas of effective field theory, nonlinear interactions between the fields…

Nuclear Theory · Physics 2009-10-30 Horst Mueller , Brian D. Serot