2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/12217A phase transition in the nature of matter in the core of a neutron star, such as quark deconfinement or Bose condensation, can cause the spontaneous spin-up of a solitary millisecond pulsar. The spin-up epoch for our model lasts for $2\times 10^7$ years or 1/50 of the spin-down time.7 pages, 4 figures, Latex (To be published in Proceedings of `Neutron Stars and Pulsars' November 1997, Tokyo by Universal Academy PressAstrophysicsNuclear Theorytext