Theoretical and Numerical Studies of Astrophysical Quark Matter: Implications to Nuclear and Explosive Astrophysics

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The search for quark matter and quark stars in the Universe: A longstanding aim of natural science is to understand the fundamental constituents of matter. Quarks and Gluons are the building blocks of the ordinary matter composed of neutrons and protons, and ordinarily remain hidden from us (i.e. they are trapped) inside protons and neutrons, requiring extreme temperature or pressure to liberate them. But nature might just do that in the ultra-dense cores of neutron stars offering us a natural laboratory to study how nuclei-free quarks can form. We developed the BURN-UD code (a first if its kind in the world) which captures the details of how neutrons inside neutron stars turn into quarks as they are squeezed by the force of gravity. We discovered that this transition can be explosive and converts the Neutron star to a Quark star (the Quark-Nova) releasing at least 10 times more energy than the most energetic Supernovae if harnessed this could be transformative to astrophysics with unique, neutrino and photon, signatures. We plan to search carefully for these signatures and improve our treatment of the physics of the explosion. Understanding how quarks can be freed from inside neutrons will advance our knowledge of matter at extreme conditions which could provide guidance for a new kind of experiments in Canada that could probe quark matter. The origin of heavy elements: The origin of the elements that make up our world is one of the oldest most fundamental scientific questions. Elements, including the carbon in our bodies and the iron that make up most of Earth, have been created by nuclear reactions in stars. However, the origin of elements beyond iron is still a mystery. They are attributed to a process called the r-process (rapid neutron capture process) which consists of seed nuclei (iron) exposed to a rich source of neutrons and ``gobbling up” as many of these neutrons as they can, yielding heavier elements. However, the site of the r-process is not known but Supernovae and colliding neutron stars are prime suspects since they produce a lots of neutrons and iron. A serious challenge is the fact that the nuclear processes governing these reactions are not well known and the properties of the extremely neutron-rich nuclei themselves are very hard to measure in laboratories. My research focuses on creating a software (a “sand-box”) for Canadian nuclear astrophysicists to simulate different astrophysical r-process sites while taking into account the uncertainties inherent to the underlying nuclear physics. Once these uncertainties are filtered out, THE astrophysical site for r-process can then be isolated. Knowing the exact site will have serious implications to the chemical evolution of the Universe. It will give us vital information about the properties of neutron-rich nuclei with direct bearing on many experiments being pursued at TRIUMF (Canada's national laboratory for particle and nuclear physics, Vancouver).