Superfluidity in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>-Stable Neutron Star Matter

Elgarøy, Ø.; Engvik, L.; Hjorth‐Jensen, M.; Osnes, E.

doi:10.1103/physrevlett.77.1428

Cited by 98 publications

(162 citation statements)

References 20 publications

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“…6 shows the number of quasi-particles in the odd and even systems for the three values of δ using the definition in Eq. (20). We note that for all cases the differences between the odd and even systems remain equal and close to one, demonstrating that the entropy is an extensive quantity as function of the number of quasiparticles.…”

Section: Entropy From a Simple Pairing Modelmentioning

confidence: 58%

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Entropy in hot161,162Dyand171
Guttormsen
¹
,
Bjerve
²
,
Hjorth‐Jensen
³

et al. 2000
Phys. Rev. C
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0
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The density of accessible levels at low spin in the ( 3 He,αγ) reaction has been extracted for the 161,162 Dy and 171,172 Yb nuclei. The entropy of the even-odd and even-even nuclei has been deduced as a function of excitation energy, and found to reach a maximum of 15 kB before neutron evaporation. The entropy of one quasi-particle outside an even-even core is found to be 1.70 (15) kB. This quasi-particle picture of hot nuclei is well accounted for within a simple pairing model. The onset of two, four and six quasi-particle excitations in the 162 Dy and 172 Yb nuclei is discussed and compared to theory. The number of quasi-particles excited per excitation energy is a measure for the ratio of the level energy spacing and the pairing strength. PACS number(s): 21.10. Ma, 24.10.Pa, 25.55.Hp, 27.70.+q

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Section: Entropy From a Simple Pairing Modelmentioning

confidence: 58%

“…This is mainly due to the strong singlet 1 S 0 state in the nucleonnucleon interaction, see e.g., Refs. [20][21][22]. For even-even systems this is typically reflected in an energy gap between the ground state and the first excited state, a gap that is larger than that seen in odd nuclei.…”

Section: Entropy From a Simple Pairing Modelmentioning

confidence: 99%

Entropy in hot161,162Dyand171
Guttormsen
¹
,
Bjerve
²
,
Hjorth‐Jensen
³

et al. 2000
Phys. Rev. C
Self Cite
38
6
40
0
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“…[69]), and relativistic effects should be examined (see, for example, ref. [70,77]). As pointed out in sect.…”

Section: Prospectusmentioning

confidence: 99%

Triplet pairing in neutron matter

Khodel¹,

Khodel²,

Clark³

2001

Nuclear Physics A

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The separation method developed earlier by us [Nucl. Phys. A598 390 (1996)] to calculate and analyze solutions of the BCS gap equation for 1 S 0 pairing is extended and applied to 3 P 2 -3 F 2 pairing in pure neutron matter. The pairing matrix elements are written as a separable part plus a remainder that vanishes when either momentum variable is on the Fermi surface. This decomposition effects a separation of the problem of determining the dependence of the gap components in a spin-angle representation on the magnitude of the momentum (described by a set of functions independent of magnetic quantum number) from the problem of determining the dependence of the gap on angle or magnetic projection. The former problem is solved through a set of nonsingular, quasilinear integral equations, providing inputs for solution of the latter problem through a coupled system of algebraic equations for a set of numerical coefficients. An incisive criterion is given for finding the upper critical density for closure of the triplet gap. The separation method and its development for triplet pairing exploit the existence of a small parameter, given by a gap-amplitude measure divided by the Fermi energy. The revised BCS equations admit analysis revealing universal properties of the full set of solutions for 3 P 2 pairing in the absence of tensor coupling, referring especially to the energy degeneracy and energetic order of these solutions. The angle-average approximation introduced by Baldo et al. is illuminated in terms of the separation-transformed BCS problem and the small parameter expansion. Numerical calculations of 3 P 2 pairing parameters and gap functions, with and without coupling to the 3 F 2 state, are carried out for pairing matrix elements supplied by (vacuum) two-neutron interactions that fit nucleon-nucleon scattering data. It is emphasized that ab initio evaluation of the in-medium particle-particle interaction and associated single-particle energies will be required if a reliable quantitative description of nucleonic superfluids is to be achieved.

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“…It is this strong nucleon-nucleon interaction of attraction that results in the formations of proton Cooper pairs and 3 P 2 anisotropic neutron Cooper pairs. The nucleonic 3 P 2 pairing gaps in NSs have been investigated by Elgarøy et al (1996) in detail. Their important results may be briefly summarized as follows:…”

Section: The Evolution Of Magnetic Fields Inside a Magnetarmentioning

confidence: 99%

Evolution of superhigh magnetic fields of magnetars

Gao

Wang²,

Yuan³

et al. 2011

Astrophys Space Sci

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In this paper, we consider the effect of Landau levels on the decay of superhigh magnetic fields of magnetars. Applying 3 P 2 anisotropic neutron superfluid theory yield a second-order differential equation for a superhigh magnetic field B and its evolutionary timescale t. The superhigh magnetic fields may evolve on timescales ∼ (10 6 − 10 7 ) yrs for common magnetars. According to our model, the activity of a magnetar may originate from instability caused by the high electron Fermi energy.

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Superfluidity inβ-Stable Neutron Star Matter

Cited by 98 publications

References 20 publications

Entropy in hot161,162Dyand171
Guttormsen
¹
,
Bjerve
²
,
Hjorth‐Jensen
³

et al. 2000
Phys. Rev. C
Self Cite
38
6
40
0
View full text Add to dashboard Cite

Entropy in hot161,162Dyand171
Guttormsen
¹
,
Bjerve
²
,
Hjorth‐Jensen
³

et al. 2000
Phys. Rev. C
Self Cite
38
6
40
0
View full text Add to dashboard Cite

Triplet pairing in neutron matter

Evolution of superhigh magnetic fields of magnetars

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Superfluidity inβ-Stable Neutron Star Matter

Cited by 98 publications

References 20 publications

Entropy in hot161,162Dyand171Guttormsen1, Bjerve2, Hjorth‐Jensen3 et al. 2000Phys. Rev. CSelf Cite386400View full textAdd to dashboardCite

Entropy in hot161,162Dyand171Guttormsen1, Bjerve2, Hjorth‐Jensen3 et al. 2000Phys. Rev. CSelf Cite386400View full textAdd to dashboardCite

Triplet pairing in neutron matter

Evolution of superhigh magnetic fields of magnetars

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Resources

About

Entropy in hot161,162Dyand171
Guttormsen
¹
,
Bjerve
²
,
Hjorth‐Jensen
³

et al. 2000
Phys. Rev. C
Self Cite
38
6
40
0
View full text Add to dashboard Cite

Entropy in hot161,162Dyand171
Guttormsen
¹
,
Bjerve
²
,
Hjorth‐Jensen
³

et al. 2000
Phys. Rev. C
Self Cite
38
6
40
0
View full text Add to dashboard Cite