arXiv subjects

Norman K. Glendenning

Publications and source records attributed to Norman K. Glendenning.

24 records · Page 2Linked to original sources

arXiv1997

Internal Constitution of Neutron and Strange Stars

In the first of these two lectures I will discuss the rich constitution of neutron stars as a consequence of the Pauli principle which is engaged by the dominance of gravity over the nuclear force. Three especially interesting phenomena are discussed in this contect--(1) a mechanism for the formation of low-mass black holes distinct in their mass-range from the black holes formed in the prompt collapse of an entire star, (2) a multilayered crystalline structure consisting of confined hadronic matter embedded in a background of deconfined quark matter (or vice versa) which occupies a many kilometer thick inner region, and (3) a clean and pronounced signal of the formation of quark matter in the interior of neutron stars. In the second lecture I will discuss the strange matter hypothesis, its viability as well as its consequences for compact stars and a new family of white dwarfs with dense nuclear matter central regions some orders of magnuitude greater than in ordinary white dwarfs.

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arXiv1997

Crystalline Structure in the Confined-Deconfined Mixed Phase: Neutron Stars

We review the differences in first order phase transition of single and multi-component systems, and then discuss the crystalline structure expected to exist in the mixed confined deconfined phase of hadronic matter. The particular context of neutron stars is chosen for illustration. The qualitative results are general and apply for example to the vapor-liquid transition in subsaturated asymmetric nuclear matter.

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arXiv1997

Finite size effects and the mixed quark-hadron phase in neutron stars

We demonstrate that the form and location (not the size or spacing) of the energetically preferred geometrical structure of the crystalline quark-hadron mixed phase in a neutron star is very sensitive to finite size terms beyond the surface term. We consider two independent approaches of including further finite size terms, namely the multiple reflection expansion of the bag model and an effective surface tension description. Thus care should be taken in any model requiring detailed knowledge of these crystalline structures.

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arXiv1997

Signal of Quark Deconfinement in the Timing Structure of Pulsar Spin-Down

The conversion of nuclear matter to quark matter in the core of a rotating neutron star alters its moment of inertia. Hence the epoch over which conversion takes place will be signaled in the spin-down "signal_prl.tex" 581 lines, 22203 characters characteristics of pulsars. We find that an observable called the braking index should be easily measurable during the transition epoch and can have a value far removed (by orders of magnitude) from the canonical value of three expected for magnetic dipole radiation, and may have either sign. The duration of the transition epoch is governed by the slow loss of angular momentum to radiation and is further prolonged by the reduction in the moment of inertia caused by the phase change which can even introduce an era of spin-up. We estimate that about one in a hundred pulsars may be passing through this phase. The phenomenon is analogous to ``bachbending'' observed in the moment of inertia of rotating nuclei observed in the 1970's, which also signaled a change in internal structure with changing spin.

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arXiv1997

Signal for the Quark-Hadron Phase Transition in Rotating Hybrid Stars

For the past 20 years it had been thought that the coexistence phase of the confined hadronic and quark matter phases, assumed to be a first order transition, was strictly excluded from neutron stars. This, however, was due to a seemingly innocuous idealization which has approximated away important physics. The reason is that neutron stars constitute multi-component bodies rather than single-component ones formerly (and incorrectly) used to describe the deconfinement phase transition in neutron stars. So, contrary to earlier claims, `neutron' stars may very well contain quark matter in their cores surrounded by a mixed-phase region of quark and hadronic matter. Such objects are called hybrid stars. The structure of such stars as well as an observable signature that could signal the existence of quark matter in their cores are discussed in this paper.

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arXiv1996

Dense Stellar Matter and Structure of Neutron Stars

After giving an overview of the history and idea of neutron stars, I shall introduce, in part one of my lectures, a representative collection of models for the equation of state of superdense neutron star matter, which account for various physical possibilities concerning the unknown behavior of such matter. Part two of my lectures deal with the construction of models of static as well as rapidly rotating neutron stars, and an investigation of the cooling behavior of such objects. Both is performed in the framework of Einstein's theory of general relativity. For this purpose the broad collection of models for the equation of state, derived in part one, will be used as an input. Various computed neutron star properties (e.g., masses, radii, moments of inertia, red and blueshifts, limiting rotational periods, cooling behavior) will be compared with the body of observed pulsar data. Finally, part three deals with an investigation of the properties of stars made up of absolutely stable strange quark matter. Their properties are compared with those of their nonstrange counterparts, i.e., neutron stars.

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