SciPost Phys. Proc. 6, 019 (2022) ·
published 31 May 2022
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We discuss masses, radii, and tidal deformabilities of neutron stars constructed from the holographic Witten-Sakai-Sugimoto model. Using the same model for crust and core of the star, we combine our theoretical results with the latest astrophysical data, thus deriving more stringent constraints than given by the data alone. For instance, our calculation predicts - independent of the model parameters - an upper limit for the maximal mass of the star of about 2.46 solar masses and a lower limit of the (dimensionless) tidal deformability of a 1.4-solar-mass star of about 277.
SciPost Phys. 11, 029 (2021) ·
published 12 August 2021
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We study baryonic matter with isospin asymmetry, including fully dynamically
its interplay with pion condensation. To this end, we employ the holographic
Witten-Sakai-Sugimoto model and the so-called homogeneous ansatz for the gauge
fields in the bulk to describe baryonic matter. Within the confined geometry
and restricting ourselves to the chiral limit, we map out the phase structure
in the presence of baryon and isospin chemical potentials, showing that for
sufficiently large chemical potentials condensed pions and isospin-asymmetric
baryonic matter coexist. We also present first results of the same approach in
the deconfined geometry and demonstrate that this case, albeit technically more
involved, is better suited for comparisons with and predictions for real-world
QCD. Our study lays the ground for future improved holographic studies aiming
towards a realistic description of charge neutral, beta-equilibrated matter in
compact stars, and also for more refined comparisons with lattice studies at
nonzero isospin chemical potential.