Ultra-Dense Neutron Star Matter, Strange Quark Stars, and the Nuclear   Equation of State
  With central densities way above the density of atomic nuclei, neutron stars contain matter in one of the densest forms found in the universe. Depending of the density reached in the cores of neutron stars, they may contain stable phases of exotic matter found nowhere else in space. This article gives a brief overview of the phases of ultra-dense matter predicted to exist deep inside neutron stars and discusses the equation of state associated with such matter. 
Fridolin Weber (San Diego State University), Matthew Meixner (San   Diego State University), Rodrigo P. Negreiros (San Diego...