Spin-up of Solitary Pulsars: Signal of Deconfinement
  A 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. 
Norman K. Glendenning (Nuclear Science Division & Institute for   Nuclear and Particle Astrophysics, Lawrence Berkeley Labor...