RUI: Probing Quark Matter through Compact Star Oscillations

California State University-Long Beach Foundation, Long Beach CA

Investigators

Abstract

The recent discovery of gravitational waves from Black Holes by the NSF-funded US-based LIGO observatories has captured the public imagination and opened a new observational window to our Cosmos, much like the discovery of the telescope did in Galileo's time. There is broad consensus in the scientific community that LIGO will soon detect gravitational waves from numerous neutron stars in our Galaxy, which were first observed by radio pulses in the 1960s. Unlike radio waves however, gravitational waves carry information about the interior of neutron stars, which will reveal new insight into nuclear physics at high density and temperature. This project is focused on improving the odds of detecting the gravitational waves from neutron stars by constructing accurate mathematical models of neutron stars and the signals they emit. Integrating nuclear physics and astrophysics, the PI will use modern computational algorithms to estimate key parameters that affect the spectrum of gravitational waves emitted by neutron stars. Results from this research will reduce the computational cost of searching for gravitational wave signals, refine existing models of nuclear physics, and train several graduate students from CSU Long Beach in the methods of scientific research. In this project, the PI will calculate the non-radial oscillation modes of compact stars made in part or entirely of strange quark matter and will study their relevance to gravitational wave signatures. The goal is to discover trends in the mode spectrum that can be used as gravitational wave fingerprints of the inner structure of neutron stars. Using theoretical principles of fluid dynamics and general relativity, supplemented by numerical routines, this research will advance the understanding of nuclear physics at high density and its implications for compact star oscillations. Novel aspects of this research include investigating the impact of composition gradients, superfluidity, and mixed phases in quark matter on the oscillation spectrum of multi-component strange/hybrid stars. The proposed methods for this research involve numerical coding to solve coupled equations of fluid dynamics in strongly gravitating spacetime inside compact stars. Through these tasks, this project will help quantify the non-radial oscillation modes for realistic quark matter equations of state, identify robust and model-dependent features of the oscillation spectrum and propose distinguishing features between neutron stars and strange stars that can be tested by gravitational wave detectors.