123 research outputs found
Strangeness in Compact Stars and Signal of Deconfinement
Phase transitions in compact stars are discussed including hyperonization,
deconfinement and crystalline phases. Reasons why kaon condensation is unlikely
is reviewed. Particular emphasis is placed on the evolution of internal
structure with spin-down of pulsars. A signature of a first order phase
transition in the timing structure of pulsars which is strong and easy to
measure, is identified.Comment: 17 pages, 15 figures, Latex. (Invited Talk at the International
Symposium on ``Strangeness In Quark Matter 1997'', Thera (Santorini), Hellas,
April 14-18, 1997, To be published in Journal of Physics G (Organizers: A
Panagiotou and J. Madsen
Spin Clustering of Accreting X-ray Neutron Stars as Possible Evidence of Quark Matter
A neutron star in binary orbit with a low-mass non-degenerate companion
becomes a source of x-rays with millisecond variability when mass accretion
spins it up. Centrifugally driven changes in density profile may initiate a
phase transition in a growing region of the core parallel to what may take
place in an isolated millisecond pulsar, but in reverse. Such a star will spend
a longer time in the spin frequency range over which the transition occurs than
elsewhere because the change of phase, paced by the spinup rate, is accompanied
by a growth in the moment of inertia. The population of accreters will exhibit
a clustering in the critical frequency range. A phase change triggered by
changing spin and the accompanying adjustment of moment of inertia has its
analogue in rotating nuclei.Comment: 5 pages (AIPproc latex) 6 figures. To be presented at the
International Conference on Nuclear Physics, 30 July - 3 August 2001,
Berkeley, Californi
Pulsar Signal of Deconfinement
A solitary millisecond pulsar, if near the mass limit, and undergoing a phase
transition, either first or second order, provided the transition is to a
substantially more compressible phase, will emit a blatantly obvious
signal---spontaneous spin-up. Normally a pulsar spins down by angular momentum
loss to radiation. The signal is trivial to detect and is estimated to be
``on'' for 1/50 of the spin-down era of millisecond pulsars. Presently about 25
solitary millisecond pulsars are known. The phenomenon is analogous to
``backbending'' observed in high spin nuclei in the 1970's.Comment: 12 pages, 11 figures, Latex-espcrc1.sty (Dec. 1997, Plenary Talk to
appear in Nuclear Physics A in the Proceedings of Quark Matter97, Tsukuba,
Japan
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