Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Massive neutron stars with holographic multiquark cores   Phases of nuclear matter are crucial in the determination of physical
properties of neutron stars~(NS). In the core of NS, the density and pressure
become so large that the nuclear matter possibly undergoes phase transition
into a deconfined phase, consisting of quarks and gluons and their colour bound
states. Even though the quark-gluon plasma has been observed in
ultra-relativistic heavy-ion collisions\cite{Gyulassy, Andronic}, it is still
unclear whether exotic quark matter exists inside neutron stars. Recent results
from the combination of various perturbative theoretical calculations with
astronomical observations\cite{Demorest, Antoniadis} shows that (exotic) quark
matter could exist inside the cores of neutron stars above 2.0 solar masses
($M_{\odot}$)~\cite{Annala:2019puf}. We revisit the holographic model in
Ref.~\cite{bch, bhp} and implement the equation of states~(EoS) of multiquark
nuclear matter to interpolate the pQCD EoS in the high-density region with the
nuclear EoS known at low densities. For sufficiently large energy density
scale~($\epsilon_{s}$) of the model, it is found that multiquark phase is
thermodynamically prefered than the stiff nuclear matter above the transition
points. The NS with holographic multiquark core could have masses in the range
$1.96-2.23~(1.64-2.10) M_{\odot}$ and radii $14.3-11.8~(14.0-11.1)$ km for
$\epsilon_{s}=26~(28)$ GeV/fm$^{3}$ respectively. Effects of proton-baryon
fractions are studied for certain type of baryonic EoS; larger proton fractions
could reduce radius of the NS with multiquark core by less than a kilometer.

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The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: eess
13
The categories of this paper are: quant-ph