The Multi-faceted Physics of General Relativistic Compact Objects

Gregory L. Comer
Department of Physics, Saint Louis University

When modelling a physical system, theorists must find the nexus between descriptions that have so many simplifying assumptions that predictions are basically empty, and those that are so saturated with detail that insight is impossible to extract. Locating this bond is perhaps the single most important goal for modelling compact objects. The most studied, other than black holes, are neutron stars (which were first detected as pulsars). They are very massive, yet small and as such require general relativistic gravity and dynamics. They are believed to have a crust, with increasingly neutron-rich nuclei - forming exotic, so-called "pasta" shapes - toward the bottom. Flowing through these nuclei are additional neutrons in a superfluid state. Just below the crust the neutron superfluid no doubt coexists with a conglomerate of superconducting protons and highly degenerate electrons (and maybe muons at higher densities). Deep inside, there are many possibilites, such as deconfined quarks in a color-flavored-locked, superconducting state. In this talk, we will discuss an intense, international effort to model compact stars (since ``neutron'' is clearly a misnomer).