Nuclear Physics Theory
Nuclear Physics Theory
The Noronha-Hostler groups studies Quantum Chromodynamics (QCD) at extreme temperatures and densities. The group performs large scale simulations on high-performance computers of heavy-ion collisions and also studies the interior of neutron stars by inferring its equation of state. The simulations of heavy-ion collisions are based upon the “standard model” of heavy-ion collisions that incorporated complex, fluctuating initial conditions into relativistic viscous fluid dynamics. In recent years, these simulations have reached an unprecedent level of precision, allowing for imaging of the nuclear structure of the colliding nuclei, searches for a potential critical point in the QCD phase diagram, and studies of the out-of-equilibrium properties of QCD at extreme temperatures and densities. The work done on neutron stars searches for interesting phases of matter such as quark or hyperon phases within the interior of neutron stars and relates these back to observable signatures through gravitational waves or X-Ray observations.
The Noronha group establishes connections between string theory, relativistic fluid dynamics, and kinetic theory to tackle outstanding problems in and out of equilibrium that are beyond the reach of current first principles techniques. A prime example of this is the fluid-like behavior displayed by the quark-gluon plasma, an exotic phase of quantum chromodynamics that existed microseconds after the Big Bang in which quarks and gluons were not confined inside protons and neutrons. Tiny specks of this early Universe matter are now being copiously produced in heavy ion collision experiments, which have provided overwhelming evidence that the quark-gluon plasma flows like a nearly frictionless strongly coupled liquid over distance scales not much larger than the size of a proton. This makes the quark-gluon plasma formed in colliders the hottest, smallest, densest, most perfect fluid known to humanity. How does fluid dynamical behavior emerge from the fundamental interactions between quarks and gluons in quantum chromodynamics? How do relativistic fluids behave far from equilibrium? These are the type of fundamental questions investigated in the group.
The group has also heavily invested in the description of the strongly-coupled quark-gluon plasma using Maldacena’s holographic duality. In this case, the strongly-coupled quark-gluon liquid is modeled via a black hole in higher dimensions, which provide a systematic way to determine the properties of strongly-coupled gauge theories both in thermodynamical equilibrium and also far from equilibrium.
Another focus of research concerns the novel phenomena displayed by viscous/dissipative fluids and plasmas under extreme conditions, such as in the presence of strong electromagnetic fields and strong gravitational fields. Neutron star mergers and relativistic plasmas near black holes provide key examples of systems current investigated in the group.
The research done in the group deals with physics problems that are intrinsically interdisciplinary and there is strong collaboration with members of the Illinois Center for Advanced Studies of the Universe (ICASU), especially in topics involving neutron stars and black holes.