Facility for Rare Isotope Beams

The origin of the chemical elements and the limits of nuclear binding are strongly linked. The heaviest elements on the periodic table are made in explosive astrophysical environments, through reactions on nuclei at the edge of existence. My work focuses on these two separate, but linked problems. I will discuss first the efforts of my group and the broader HiRA collaboration to study the nuclear equation of state (EoS) through collisions of heavy ions. The nuclear EoS underpins our understanding of how nucleons assemble themselves from finite nuclei to neutron stars. With the next generation accelerator facilities coming online, the nuclear science community is poised to further improve our understanding of the nature of neutron-rich nuclear matter with terrestrial measurements. I will discuss our recent results from data taken at NSCL, and discuss our future plans with the new opportunities afforded by the Facility for Rare Isotope beams. I will then discuss my work on two-proton decay. These unbound nuclei allow one to glimpse the underlying nuclear potential and provide a test of our nuclear models.

Committee: Wu, Xing [Chairperson], Becker, Jonas Nils, Cocker, Tyler L, Severin, Gregory William, Singh, Jaideep Taggart

*Please note that this seminar will take place at 10am Eastern Time Neutron Stars are born in core-collapse supernovae being the endpoint of stellar evolution of massive stars. Their extreme properties allow for the study of dense matter in the sky. In recent years the advancement of astrophysical observations has been so tremendous that the properties of neutron stars can be constrained nowadays to an unprecedented level. I will summarize the basic observations of neutron star masses from pulsar data, the constraints on radii from x-ray measurements, and the first detection of gravitational waves from a neutron star merger. On the other hand, I will discuss the nuclear and particle physics aspects of the equation of state of neutron star matter which is firmly limited at low and high energy densities. Chiral effective field theory puts a stringent constraint up to about saturation density for pure neutron matter. Perturbative QCD calculations narrow the equation of state at ultimately high densities. Finally, I will address the possible existence of new phases in the core of neutron stars which can be revealed from the mass-radius relation of neutron stars. I will argue that it is in principle impossible to rule out phase transitions in neutron stars from observations based on general relativity alone. Speaker Homepage: https://astro.uni-frankfurt.de/schaffner/

Quantum computers offer the potential to simulate nuclear processes that are classically intractable. With the goal of understanding the necessary quantum resources, we employ state-of-the-art Hamiltonian-simulation methods, and conduct a thorough algorithmic analysis, to estimate the qubit and gate costs to simulate low-energy effective field theories (EFTs) of nuclear physics. In particular, within the framework of nuclear lattice EFT, we obtain simulation costs for the leading-order pionless and pionful EFTs. We consider both static pions represented by a one-pion-exchange potential between the nucleons, and dynamical pions represented by relativistic bosonic fields coupled to non-relativistic nucleons. We examine the resource costs for the tasks of time evolution and energy estimation for physically relevant scales. We account for model errors associated with truncating either long-range interactions in the one-pion-exchange EFT or the pionic Hilbert space in the dynamical-pion EFT, and for algorithmic errors associated with product-formula approximations and quantum phase estimation. Our results show that the pionless EFT is the least costly to simulate and the dynamical-pion theory is the costliest. We demonstrate how symmetries of the low-energy nuclear Hamiltonians can be utilized to obtain tighter error bounds on the simulation algorithm. By retaining the locality of nucleonic interactions when mapped to qubits, we achieve reduced circuit depth and substantial parallelization. This work highlights the importance of combining physics insights and algorithmic advancement in reducing quantum-simulation costs.

“The metric system, now officially known as the International System of Units (SI), was born with the French revolution. It has recently undergone its most revolutionary reform since that birth. Famously, the kilogram is no longer defined as the mass of an artifact, the International Prototype Kilogram, but rather is now a quantum concept, defined by fixing the value of Planck’s constant. In fact, all of the base units of the SI are defined by fixing the values of natural constants, and the SI now has a distinctly quantum flavor. The quantization of charge allows us to fix the charge of the electron, defining the ampere as a certain number of electrons per second. The unit of temperature, the kelvin, is no longer based on the triple point of water, but on the thermal energy of the atomic/molecular components of matter, by fixing the value of Boltzmann’s constant. The unit of time has long been quantum, but its impending re-definition will make it even more so.”

Bio

William D. Phillips received a bachelor’s degree in physics from Juniata College in 1970, and a PhD from the Massachusetts Institute of Technology (MIT) in 1976. After two years as a Chaim Weizmann postdoctoral fellow at MIT, he joined the National Institute of Standards and Technology (NIST) – then known as the National Bureau of Standards – to work on precision electrical measurements and fundamental constants. There, he initiated a new research program to cool atomic gases with laser light. He founded NIST’s Laser Cooling and Trapping Group, and later was a founding member of the Joint Quantum Institute, a cooperative research organization of NIST and the University of Maryland that is devoted to the study of quantum coherent phenomena. His research group has been responsible for developing some of the main techniques now used for laser-cooling and cold-atom experiments in laboratories around the world. Their achievements include the first electromagnetic trapping of neutral atoms; reaching unexpectedly low laser-cooling temperatures, within a millionth of a degree of Absolute Zero; the confinement of atoms in optical lattices; and coherent atom-optical manipulation of atomic-gas Bose-Einstein condensates. Atomic fountain clocks, based on the work of this group, are now the primary standards for world timekeeping and lattice-trapped atoms are among the likely candidates for future primary frequency standards. Among the group’s current research directions are the use of ultra-cold atoms for quantum information processing and quantum simulation of important physical problems.

Phillips is a fellow of the American Physical Society, the American Association for the Advancement of Science, and the American Academy of Arts and Sciences. He is a Fellow and Honorary Member of OPTICA (formerly the Optical Society), a member of the National Academy of Sciences and the Pontifical Academy of Sciences, and a corresponding member of the Mexican Academy of Sciences. In 1997, Phillips shared the Nobel Prize in Physics "for development of methods to cool and trap atoms with laser light."

The STREAMLINE (SmarT Reduction and Emulation Applying Machine Learning In Nuclear Environments) collaboration aims to advance the frontiers of theoretical and computational research on the nuclear many-body problem using ML. The scientific problems we address are among the most challenging in computational nuclear many-body theory and the collaboration is aligned with the U.S. government initiative to build a broad-based, multidisciplinary, multi-agency program for a sustained national AI structure. STREAMLINE will advance large nuclear physics computations to dramatically increase predictive power and improve our understanding of nuclear structure and dynamics, dense nucleonic matter, and emergent many-body phenomena -- this includes the properties of heavy neutron-rich nuclei and related astrophysical environments at the Facility for Rare Isotope Beams (FRIB); structure and reactions of nuclei and nuclear astrophysics at the Argonne Tandem Linac Accelerator System (ATLAS); neutron distributions in nuclei and few-body systems at Thomas Jefferson National Accelerator Facility (TJNAF); properties of fission at Los Alamos Neutron Science Center (LANSCE); and nuclear structure, reactions, and astrophysics at Association for Research at University Nuclear Accelerator facilities (ARUNA).

The Nuclear Science Summer School (NS3) is a summer school that introduces undergraduate student participants to the fields of nuclear science and nuclear astrophysics. NS3 is hosted by FRIB on the campus of Michigan State University (MSU). The school will offer lectures and activities covering selected nuclear science and astrophysics topics.