Quakes in solid quark stars

As a result of observational difficulties, braking indices of only six rotation-powered pulsars are obtained with certainty, all of which are remarkably smaller than the value (n = 3) expected for pure magnetodipole radiation model. This is still a real fundamental question not being well answered after nearly forty years of the discovery of pulsar. The main problem is that we are shamefully not sure about the dominant mechanisms that result in pulsars' spin-down. Based on the previous works, the braking index is re-examined, with a conclusion of suggesting a constant gap potential drop for pulsars with magnetospheric activities. New constrains on model parameters from observed braking indices are presented.

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“…The pulsar is a spherical when Ω = 0 and is a rotation ellipsoid when Ω > 0. We have (Zhou et al, 2004)…”

Section: The Volume Conservative Casementioning

confidence: 99%

“…A rotating star, or specifically a pulsar, can be approximately as an Maclaurin rotation ellipsoid when the spin period is not too small (Zhou et al, 2004). For pulsars, the criteria is P ≫ 1 ms, so the rotation ellipsoid approximation are available for all the six pulsar in this article.…”

Section: The Volume Conservative Casementioning

confidence: 99%

What can the braking indices tell us about the nature of pulsars?

Yue

Zhu

2007

Advances in Space Research

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“…Quakes of solid QSs may result in pulsar glitches [39] and bursts (even superflares) of anomalous X-ray pulsars/soft gamma-ray repeaters [34]. Actually there are two kinds of stress force inside solid stars: bulk-invariable and bulk-variable forces, both of which could result in decreases of moment of inertia, and thus in pulsar glitches.…”

Section: Possible Evidence For Quark Starsmentioning

confidence: 99%

Possible evidence that pulsars are quark stars

Xu¹

2008

AIP Conference Proceedings

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Abstract. It is a pity that the real state of matter in pulsar-like stars is still not determined confidently because of the uncertainty about cold matter at supranuclear density, even 40 years after the discovery of pulsar. Nuclear matter (related to neutron stars) is one of the speculations for the inner constitution of pulsars even from the Landau's time more than 70 years ago, but quark matter (related to quark stars) is an alternative due to the fact of asymptotic freedom of interaction between quarks as the standard model of particle physics develops since 1960s. Therefore, one has to focus on astrophysical observations in order to answer what the nature of pulsars is. In this presentation, I would like to summarize possible observational evidence/hints that pulsar-like stars could be quark stars, and to address achievable clear evidence for quark stars in the future experiments.Keywords: Pulsars, Quark matter, Neutron stars PACS: 97.60.Gb, 21.65.Qr, 97.60.Jd Introduction: pulsars and cold quark matterIt is a puerile desire to know the fundamental constituents of matter and the interactions between them. Elemental fermions (quarks and leptons) are supposed to be the building blocks, between which fundamental interaction occurs via exchanging gauge bosons, in the standard model of particle physics that is one of most prominent achievements in the last century. QCD (quantum chromo-dynamics) is believed to be the underlying theory of the elementary strong interaction between quarks, which is relatively poorly understood compared with others (except for the planck-scale gravity). QCD has been precisely tested in the high energy limit due to the asymptotic freedom, while it becomes one of the daunting challenges nowadays to understand QCD in the low energy regime because of QCD's highly nonperturbative nature. The aspects of nonperturbative QCD include the argument of color confinement (would color states be really single? [17]) and possible phases of quark matter (i.e., matter composed of quarks as fermions).It is a simple motivation idea to explore the Universe. One of the attractive questions is about stars: their formation, evolution, and death. Pulsars, discovered 40 years ago, are the residues of massive main sequent stars during supernovae, which were suggested to be normal neutron stars (the most original one was speculated by Landau more than 70 years ago) soon after the discovery, but were suspected to be quark stars (QSs) as the quark model for hadrons develops since 1960s. Pulsars are one kind of so-called compact stars, whose average density is beyond the nuclear density, ρ nucl . Thanks to advanced facilities, very different manifestations of pulsar-like stars are observed recently, and many important astrophysics depends certainly on the real nature of pulsars.Both particle physicists and astrophysicists meet together when trying to answer what the nature of matter at supranuclear density is. Neutron matter was proposed long before our recognizing the structure of hadrons, and could certainly exi...

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“…Two scenarios of such astrophysical quark matter: quark stars and ultrahigh energy cosmic rays. Fortunately and excitedly, many astrophysical challenges could not exist any more in the solid quark star model for pulsar-like stars, e.g., the thermal X-ray spectra (Xu 2003) and the discrepancy between glitches and free-precessions (Zhou et al 2004). …”

Section: Quark Matter In Compact Stars and As Cosmic Raysmentioning

confidence: 99%

Astrophysical Quark Matter

2005

Chin. J. Astron. Astrophys.

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Quakes in solid quark stars

Cited by 59 publications

References 27 publications

What can the braking indices tell us about the nature of pulsars?

What can the braking indices tell us about the nature of pulsars?

Possible evidence that pulsars are quark stars

Astrophysical Quark Matter

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