The Einstein theory of general relativity predicts the existence of gravitational waves, which are literally ripples of curvature in the fabric of space and time that are generated whenever massive objects oscillate. Among the best sources for gravitational waves are neutron stars, which are the remnants of supernovae, the spectacular explosions that result when the cores of heavy stars collapse after they have exhausted their nuclear fuel. After a few months of cooling, the core of a neutron star is predicted to become superfluid, a special state of matter that can flow with no friction and can rotate only by forming a dense array of Ultra-thin vortices --- very skinny tornados --- that thread the star. This project will develop computer-based models of the oscillations of superfluid neutron stars and the gravitational waves that they emit.
Because of the special properties of superfluid matter, the modes of oscillation of a superfluid neutron star should be very different from those of an ordinary fluid star. Consequently, the gravitational waves that are created from their oscillations should carry a distinct signature of superfluidity. Suitably advanced gravitational wave detectors should be able to extract this signature from the gravitational wave data. Because of their extreme mass (on the order of the same mass as the Sun) and compact size (about 20 kilometers in diameter), neutron stars represent a form of matter that cannot be created in Earth-based laboratories. Direct detection of gravitational waves thus allows neutron stars to become, in effect, astrophysical laboratories for the study of matter under the most extreme conditions.
