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Related papers: Isospin Equilibration in Neutron Star Mergers

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We show that the commonly used criterion for beta equilibrium in neutrino-transparent dense nuclear matter becomes invalid as temperatures rise above 1 MeV. Such temperatures are attained in neutron star mergers. By numerically computing…

Nuclear Theory · Physics 2019-01-02 Mark G. Alford , Steven P. Harris

In this paper, we discuss the damping of density oscillations in dense nuclear matter in the temperature range relevant to neutron star mergers. This damping is due to bulk viscosity arising from the weak interaction ``Urca'' processes of…

Nuclear Theory · Physics 2020-06-23 Mark Alford , Arus Harutyunyan , Armen Sedrakian

We discuss the bulk viscosity of hot and dense $npe\mu$ matter arising from weak-interaction direct Urca processes. We consider two regimes of interest: (a) the neutrino-transparent regime with $T\leq T_{\rm tr}$ ($T_{\rm tr}\simeq 5\div…

High Energy Astrophysical Phenomena · Physics 2022-09-13 Mark Alford , Arus Harutyunyan , Armen Sedrakian

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

We calculate the bulk-viscous dissipation time for adiabatic density oscillations in nuclear matter at densities of 1-7 times nuclear saturation density and at temperatures ranging from 1 MeV, where corrections to previous low-temperature…

Nuclear Theory · Physics 2019-10-02 Mark G. Alford , Steven P. Harris

In order to extract maximal information from neutron-star merger signals, both gravitational and electromagnetic, we need to ensure that our theoretical models/numerical simulations faithfully represent the extreme physics involved. This…

High Energy Astrophysical Phenomena · Physics 2021-11-09 Peter Hammond , Ian Hawke , Nils Andersson

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…

Nuclear Theory · Physics 2014-02-26 J. A. López , E. Ramírez-Homs , R. González , R. Ravelo

We investigate the density behaviour of the symmetry energy with respect to isospin equilibration in the combined systems $Ru(Zr)+Zr(Ru)$ at relativistic energies of 0.4 and $1.528 AGeV$. The study is performed within a relativistic…

Nuclear Theory · Physics 2009-11-10 T. Gaitanos , M. Colonna , M. Di Toro , H. H. Wolter

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

Based on an improved isospin- and momentum-dependent interaction, we have studied the qualitative effect of isospin splitting of nucleon effective mass on the specific shear viscosity of neutron-rich nuclear matter from a relaxation time…

Nuclear Theory · Physics 2015-03-04 Jun Xu

The isospin equilibration process in multinucleon transfer reaction is investigated by using the improved quantum molecular dynamics model. The collision processes of $^{124}$Xe+$^{208}$Pb at near-barrier energy are studied with different…

Nuclear Theory · Physics 2019-04-03 Cheng Li , Cheikh A. T. Sokhna , Xinxin Xu , Jingjing Li , Gen Zhang , Bing Li , Zhishuai Ge , Feng-Shou Zhang

Merging neutron stars are expected to produce hot, metastable remnants in rapid differential rotation, which subsequently cool and evolve into rigidly rotating neutron stars or collapse to black holes. Studying this metastable phase and its…

High Energy Astrophysical Phenomena · Physics 2021-03-19 Giovanni Camelio , Tim Dietrich , Stephan Rosswog , Brynmor Haskell

We study out-of-thermodynamic equilibrium effects in neutron star mergers with 3D general-relativistic neutrino-radiation large-eddy simulations. During merger, the cores of the neutron stars remain cold ($T \sim$ a few MeV) and out of…

We calculate the nonzero-temperature correction to the beta equilibrium condition in nuclear matter under neutron star merger conditions, in the temperature range $1\,$MeV$ < T \lesssim 5\,$MeV. We improve on previous work by using a…

Nuclear Theory · Physics 2023-10-10 Mark G. Alford , Alexander Haber , Steven P. Harris , Ziyuan Zhang

In this paper we present a computation of the rates of strangeness-changing processes and the resultant bulk viscosity in matter at the densities and temperatures typical of neutron star mergers. To deal with the high temperature in this…

Nuclear Theory · Physics 2021-05-05 Mark G. Alford , Alexander Haber

We perform three-dimensional relativistic hydrodynamical calculations of neutron star mergers to assess the reliability of an approximate treatment of thermal effects in such simulations by combining an ideal-gas component with…

Solar and Stellar Astrophysics · Physics 2010-11-11 A. Bauswein , H. -Th. Janka , R. Oechslin

The roles of isospin asymmetry in nuclei and neutron stars are investigated using a range of potential and field-theoretical models of nucleonic matter. The parameters of these models are fixed by fitting the properties of homogeneous bulk…

Nuclear Theory · Physics 2009-11-11 Andrew W. Steiner , Madappa Prakash , James M. Lattimer , Paul J. Ellis

The roles of isospin asymmetry in nuclei and neutron stars are investigated using a range of potential and field-theoretical models of nucleonic matter. The parameters of these models are fixed by fitting the properties of homogeneous bulk…

Nuclear Theory · Physics 2008-11-26 Andrew W. Steiner , Madappa Prakash , James M. Lattimer , Paul J. Ellis

The equation of state of asymmetric nuclear matter is still controversial, as predictions at subsaturation as well as above normal density widely diverge. We discuss several experimental results measured in heavy-ion collisions with the…

The accurate measurement of neutron skin thickness of $^{208}$Pb by the PREX Collaboration suggests a large value of the nuclear symmetry energy slope parameter, $L$, whereas the smaller $L$ is preferred to account for the small…

Nuclear Theory · Physics 2025-03-07 Tsuyoshi Miyatsu , Myung-Ki Cheoun , Kyungsik Kim , Koichi Saito
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