Chiral pasta: Mixed phases at the chiral phase transition
Chiral pasta: Mixed phases at the chiral phase transition
Interiors of neutron stars are ultradense and may contain a core of deconfined quark matter. Such a core connects to the outer layers smoothly or through a sharp microscopic interface or through an intermediate macroscopic layer of inhomogeneous mixed phases, which is globally neutral but locally contains electrically charged domains. Here I employ a nucleon-meson model under neutron star conditions that shows a first-order chiral phase transition at large densities. In the vicinity of this chiral transition I calculate the free energies of various mixed phases - different "pasta structures" - in the Wigner-Seitz approximation. Crucially, chirally broken nuclear matter and the approximately chirally symmetric phase (loosely interpreted as quark matter) are treated on the same footing. This allows me to compute the interface profiles of bubbles, rods, and slabs fully consistently, taking into account electromagnetic screening effects and without needing the surface tension as an input. I find that the full numerical results tend to disfavor mixed phases compared to a simple steplike approximation used frequently in the literature and that the predominantly favored pasta structure consists of slabs with a surface tension ς≃6 MeV/fm2.
hep-ph, astro-ph.HE, nucl-th
Schmitt, Andreas
1765159f-255f-45e7-94ea-58c1c883d65f
7 April 2020
Schmitt, Andreas
1765159f-255f-45e7-94ea-58c1c883d65f
Abstract
Interiors of neutron stars are ultradense and may contain a core of deconfined quark matter. Such a core connects to the outer layers smoothly or through a sharp microscopic interface or through an intermediate macroscopic layer of inhomogeneous mixed phases, which is globally neutral but locally contains electrically charged domains. Here I employ a nucleon-meson model under neutron star conditions that shows a first-order chiral phase transition at large densities. In the vicinity of this chiral transition I calculate the free energies of various mixed phases - different "pasta structures" - in the Wigner-Seitz approximation. Crucially, chirally broken nuclear matter and the approximately chirally symmetric phase (loosely interpreted as quark matter) are treated on the same footing. This allows me to compute the interface profiles of bubbles, rods, and slabs fully consistently, taking into account electromagnetic screening effects and without needing the surface tension as an input. I find that the full numerical results tend to disfavor mixed phases compared to a simple steplike approximation used frequently in the literature and that the predominantly favored pasta structure consists of slabs with a surface tension ς≃6 MeV/fm2.
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Chiral pasta
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e-pub ahead of print date: 7 February 2020
Published date: 7 April 2020
Additional Information:
Funding Information:
I am grateful to M. Alford, S. Carignano, E. Fraga, M. Hippert, A. Pfaff, K. Rajagopal, and A. Sedrakian for valuable discussions and comments. I am supported by the Science & Technology Facilities Council (STFC) in the form of an Ernest Rutherford Fellowship.
Publisher Copyright:
© 2020 authors. Published by the American Physical Society.
Keywords:
hep-ph, astro-ph.HE, nucl-th
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Local EPrints ID: 440779
URI: http://eprints.soton.ac.uk/id/eprint/440779
ISSN: 1550-7998
PURE UUID: b8a9953e-8a68-4689-a7d8-28de8ac5a15c
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Date deposited: 18 May 2020 16:33
Last modified: 17 Mar 2024 03:40
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