Abstract

Formed in the aftermath of gravitational core-collapse supernova explosions, neutron stars contain matter crushed at densities exceeding that found inside the heaviest atomic nuclei and are therefore unique laboratories for exploring novel phases of matter under conditions so extreme that they cannot be reproduced on Earth. In particular, neutron stars are the only celestial bodies that are expected to contain frictionless quantum liquids. Although such superfluids have been extensively studied in the laboratory, the properties of their stellar counterpart still remain largely unknown. The main difficulty lies in the widely different scales involved: rotating superfluid neutron stars (whose radius is about 10 kilometres) are thought to be threaded by quantized vortices with tiny cores of about 10-100 fermis and separated by a typical distance of 0.1 microns. To add to the challenge, a neutron star is so compact (having a mass between once and twice that of the Sun) that it must be described by Einstein’s theory of general relativity. During this talk, I will present recent developments in the understanding of superfluidity in neutron stars.