Neutron Star Physics: From Supernova Birth to Exotic Interiors

Neutron stars provide unique laboratories for studying matter under extreme conditions, from the outer atmosphere to the ultra-dense core. This review covers the formation of neutron stars in core-collapse supernovae and details their layered internal structure, including the atmosphere, envelope, crust, and dense nuclear core. We discuss key physical processes such as neutrino cooling, superfluidity, superconductivity, and the role of quantum condensates in shaping neutron star behavior. The interplay of superfluid vortices and magnetic flux tubes explains observed phenomena like pulsar glitches, while strong magnetic fields govern spin evolution and high-energy emission. Advances in mass and radius measurements from X-ray and gravitational-wave observations are constraining the equation of state of dense nuclear matter. By combining theoretical insights and observations, this work summarizes current knowledge of neutron star interiors and outlines future pathways for understanding matter at supranuclear densities.