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Title: Isospin asymmetry and type-I superconductivity in neutron star matter

Abstract

It has been argued by Buckley et al. [1] that nuclear matter is a type-I rather than a type-II superconductor. The suggested mechanism is a strong interaction between neutron and proton Cooper pairs, which arises from an assumed U(2) symmetry of the effective potential, which is supposed to originate in isospin symmetry of the underlying nuclear interactions. To test this claim, we perform an explicit mean-field calculation of the effective potential of the Cooper pairs in a model with a simple four-point pairing interaction. In the neutron star context, matter is very neutron rich with less than 10% protons, so there is no neutron-proton pairing. We find that under these conditions our model shows no interaction between proton Cooper pairs and neutron Cooper pairs at the mean-field level. We estimate the leading contribution beyond mean field and find that it is small and attractive at weak coupling.

Authors:
;  [1];  [2]
  1. Physics Department, Washington University, St. Louis, Missouri 63130 (United States)
  2. Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Publication Date:
OSTI Identifier:
20699144
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 72; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.72.055801; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; ASYMMETRY; BCS THEORY; COOPER PAIRS; COUPLING; ISOSPIN; MEAN-FIELD THEORY; NEUTRON STARS; NEUTRONS; NUCLEAR MATTER; PAIRING INTERACTIONS; POTENTIALS; PROTONS; STRONG INTERACTIONS; SUPERCONDUCTIVITY; SYMMETRY; TYPE-I SUPERCONDUCTORS; U-2 GROUPS

Citation Formats

Alford, Mark, Good, Gerald, and Reddy, Sanjay. Isospin asymmetry and type-I superconductivity in neutron star matter. United States: N. p., 2005. Web. doi:10.1103/PhysRevC.72.055801.
Alford, Mark, Good, Gerald, & Reddy, Sanjay. Isospin asymmetry and type-I superconductivity in neutron star matter. United States. doi:10.1103/PhysRevC.72.055801.
Alford, Mark, Good, Gerald, and Reddy, Sanjay. Tue . "Isospin asymmetry and type-I superconductivity in neutron star matter". United States. doi:10.1103/PhysRevC.72.055801.
@article{osti_20699144,
title = {Isospin asymmetry and type-I superconductivity in neutron star matter},
author = {Alford, Mark and Good, Gerald and Reddy, Sanjay},
abstractNote = {It has been argued by Buckley et al. [1] that nuclear matter is a type-I rather than a type-II superconductor. The suggested mechanism is a strong interaction between neutron and proton Cooper pairs, which arises from an assumed U(2) symmetry of the effective potential, which is supposed to originate in isospin symmetry of the underlying nuclear interactions. To test this claim, we perform an explicit mean-field calculation of the effective potential of the Cooper pairs in a model with a simple four-point pairing interaction. In the neutron star context, matter is very neutron rich with less than 10% protons, so there is no neutron-proton pairing. We find that under these conditions our model shows no interaction between proton Cooper pairs and neutron Cooper pairs at the mean-field level. We estimate the leading contribution beyond mean field and find that it is small and attractive at weak coupling.},
doi = {10.1103/PhysRevC.72.055801},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 72,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}
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