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Title: Phenomenological QCD equation of state for massive neutron stars

Abstract

Here, we construct an equation of state for massive neutron stars based on quantum chromodynamics phenomenology. Our primary purpose is to delineate the relevant ingredients of equations of state that simultaneously have the required stiffness and satisfy constraints from thermodynamics and causality. These ingredients are (i) a repulsive density-density interaction, universal for all flavors, (ii) the color-magnetic interaction active from low to high densities, (iii) confining effects, which become increasingly important as the baryon density decreases, and (iv) nonperturbative gluons, which are not very sensitive to changes of the quark density. We use the following “3-window” description: At baryon densities below about twice normal nuclear density, 2n 0, we use the Akmal-Pandharipande-Ravenhall (APR) equation of state, and at high densities, ≥(4–7)n 0, we use the three-flavor Nambu-Jona-Lasinio (NJL) model supplemented by vector and diquark interactions. In the transition density region, we smoothly interpolate the hadronic and quark equations of state in the chemical potential-pressure plane. Requiring that the equation of state approach APR at low densities, we find that the quark pressure in nonconfining models can be larger than the hadronic pressure, unlike in conventional equations of state. We show that consistent equations of state of stiffness sufficient to allowmore » massive neutron stars are reasonably tightly constrained, suggesting that gluon dynamics remains nonperturbative even at baryon densities ~10n 0.« less

Authors:
 [1];  [2];  [1];  [3]
  1. Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)
  2. Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States); RIKEN, Wako (Japan)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1438702
Report Number(s):
LLNL-JRNL-739920
Journal ID: ISSN 1550-7998; PRVDAQ; TRN: US1900493
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review. D, Particles, Fields, Gravitation and Cosmology
Additional Journal Information:
Journal Volume: 91; Journal Issue: 4; Journal ID: ISSN 1550-7998
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 79 ASTRONOMY AND ASTROPHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

Kojo, Toru, Powell, Philip D., Song, Yifan, and Baym, Gordon. Phenomenological QCD equation of state for massive neutron stars. United States: N. p., 2015. Web. doi:10.1103/PhysRevD.91.045003.
Kojo, Toru, Powell, Philip D., Song, Yifan, & Baym, Gordon. Phenomenological QCD equation of state for massive neutron stars. United States. doi:10.1103/PhysRevD.91.045003.
Kojo, Toru, Powell, Philip D., Song, Yifan, and Baym, Gordon. Tue . "Phenomenological QCD equation of state for massive neutron stars". United States. doi:10.1103/PhysRevD.91.045003. https://www.osti.gov/servlets/purl/1438702.
@article{osti_1438702,
title = {Phenomenological QCD equation of state for massive neutron stars},
author = {Kojo, Toru and Powell, Philip D. and Song, Yifan and Baym, Gordon},
abstractNote = {Here, we construct an equation of state for massive neutron stars based on quantum chromodynamics phenomenology. Our primary purpose is to delineate the relevant ingredients of equations of state that simultaneously have the required stiffness and satisfy constraints from thermodynamics and causality. These ingredients are (i) a repulsive density-density interaction, universal for all flavors, (ii) the color-magnetic interaction active from low to high densities, (iii) confining effects, which become increasingly important as the baryon density decreases, and (iv) nonperturbative gluons, which are not very sensitive to changes of the quark density. We use the following “3-window” description: At baryon densities below about twice normal nuclear density, 2n0, we use the Akmal-Pandharipande-Ravenhall (APR) equation of state, and at high densities, ≥(4–7)n0, we use the three-flavor Nambu-Jona-Lasinio (NJL) model supplemented by vector and diquark interactions. In the transition density region, we smoothly interpolate the hadronic and quark equations of state in the chemical potential-pressure plane. Requiring that the equation of state approach APR at low densities, we find that the quark pressure in nonconfining models can be larger than the hadronic pressure, unlike in conventional equations of state. We show that consistent equations of state of stiffness sufficient to allow massive neutron stars are reasonably tightly constrained, suggesting that gluon dynamics remains nonperturbative even at baryon densities ~10n0.},
doi = {10.1103/PhysRevD.91.045003},
journal = {Physical Review. D, Particles, Fields, Gravitation and Cosmology},
number = 4,
volume = 91,
place = {United States},
year = {2015},
month = {2}
}

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