From Nuclear Droplets to Compact Stars

Dr. Panagiota Papakonstantinou (host Dickhoff), Institute for Basic Science Rare Isotope Science Project, Daejeon, South Korea
January 24, 2018 at 4:00 pm
204 Crow
Event Description 

Last August, the merging of two neutron stars made waves, gravitational but also metaphorical, as the furnace where precious metals are cooked - an alchemist's dream. To anticipate, detect, and make any sense of such an event's signals takes a lot of ingenuity on many fronts, while the observations provide valuable feedback to our understanding of nature. As in any dynamical situation, whether smooth or cataclysmic, whether in the skies or in a water tank, one elementary question to ask is: what material are we dealing with? That is, what are its properties and affinities, and how can we predict its behavior in different conditions? To put it simply, what is a neutron star made of and how can it spew gold?

Answers can be found at length scales roughly 10^{18} times smaller, here on Earth, in the femto-sized object at the core of every atom. Atomic nuclei are, in effect, droplets of "nuclear stuff", the stuff of compact stars, obeying a specific equation of state and phase diagram. They can fuse together, fission, or absorb other particles to make new elements. We observe them through their strong, weak, and electromagnetic interactions at experimental facilities and model them as quantum many-body systems, in math and in computer code.

In this talk I will focus on the collective behavior of atomic nuclei, in particular small-amplitude motion akin to sound waves, and what it can tell us about the nuclear equation of state and compact stars. I will also venture into the opposite direction and illustrate how astronomical observations can guide us to modeling nucleonic systems and making predictions to be tested at rare-isotope facilities in the near future.

Coffee: 3:30 pm, 245 Compton