Signatures of quark-hadron phase transitions in general-relativistic neutron-star mergers. (arXiv:1807.03684v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Most_E/0/1/0/all/0/1">Elias R. Most</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Papenfort_L/0/1/0/all/0/1">L. Jens Papenfort</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dexheimer_V/0/1/0/all/0/1">Veronica Dexheimer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hanauske_M/0/1/0/all/0/1">Matthias Hanauske</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schramm_S/0/1/0/all/0/1">Stefan Schramm</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stocker_H/0/1/0/all/0/1">Horst Stöcker</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rezzolla_L/0/1/0/all/0/1">Luciano Rezzolla</a>
Merging binaries of neutron stars are not only strong sources of
gravitational waves, but also have the potential of revealing states of matter
at densities and temperatures not accessible in laboratories. A crucial and
long-standing question in this context is whether quarks are deconfined as a
result of the dramatic increase in density and temperature following the
merger. We present the first fully general-relativistic simulations of merging
neutron stars including quarks at finite temperatures that can be switched off
consistently in the equation of state. Within our approach, we can determine
clearly what signatures a quark-hadron phase transition would leave in the
gravitational-wave signal. In particular, we show that if the conditions are
met for a phase transition to take place at several times nuclear saturation
density, they would lead to a post-merger signal considerably different from
the one expected from the inspiral, that can only probe the hadronic part of
the equations of state, and to an anticipated collapse of the merged object. We
also show that the phase transition leads to a very hot and dense quark core
that, when it collapses to a black hole, produces a ringdown signal different
from the hadronic one. Finally, in analogy with what is done in heavy-ion
collisions, we use the evolution of the temperature and density in the merger
remnant to illustrate the properties of the phase transition in a QCD phase
diagram.
Merging binaries of neutron stars are not only strong sources of
gravitational waves, but also have the potential of revealing states of matter
at densities and temperatures not accessible in laboratories. A crucial and
long-standing question in this context is whether quarks are deconfined as a
result of the dramatic increase in density and temperature following the
merger. We present the first fully general-relativistic simulations of merging
neutron stars including quarks at finite temperatures that can be switched off
consistently in the equation of state. Within our approach, we can determine
clearly what signatures a quark-hadron phase transition would leave in the
gravitational-wave signal. In particular, we show that if the conditions are
met for a phase transition to take place at several times nuclear saturation
density, they would lead to a post-merger signal considerably different from
the one expected from the inspiral, that can only probe the hadronic part of
the equations of state, and to an anticipated collapse of the merged object. We
also show that the phase transition leads to a very hot and dense quark core
that, when it collapses to a black hole, produces a ringdown signal different
from the hadronic one. Finally, in analogy with what is done in heavy-ion
collisions, we use the evolution of the temperature and density in the merger
remnant to illustrate the properties of the phase transition in a QCD phase
diagram.
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