LSU Researchers Progress Our Knowledge on the Important Implications for Understanding the Physics of Nuclei

(a) The symplectic group   Sp ( 3 , R )   consists of all particle-independent linear canonical transformations   ( A C B D )   of the single-particle phase-space observables   → r i   (position) and   → p i   (momentum) that preserve the Heisenberg commutation relations   [ r α i , p α ′ j ] = i ℏ δ α α ′ δ i j  ,   α , α ′ = x  ,   y  ,   z   [40]. (b) In the shell model, the basis configurations are multiples of symplectic excitations, generated by   r 2   and   Q  . A key feature is that a single-particle   Sp ( 3 , R )   irreducible representation spans all positive-(or negative-)parity states for a particle in a 3D spherical or deformed harmonic oscillator.

Physics journal PRL features LSU nuclear physics research

Physical Review Letters, PRL, the world’s premier physics letter journal, has published a paper by a team of LSU nuclear physics researchers to advance the knowledge on the important implications for understanding the physics of nuclei.

In their paper, Physics of Nuclei: Key Role of an Emergent Symmetry, Phys. Rev. Lett. 124, 042501, they show through first-principles nuclear structure calculations that the special nature of the strong nuclear force determines highly regular patterns heretofore unrecognized in nuclei that can be tied to an emergent approximate symmetry. This, in turn, has important implications for understanding the physics of nuclei: they find that nuclei are made of only a few equilibrium shapes, deformed or not, with associated vibrations and rotations. It also opens the path for ab initio large-scale modeling of heavier-mass nuclei

 “These are remarkable findings – no one expected, even practitioners in this area, that this symmetry would be anything as good and widespread as we now show it to be,” said Assistant Professor Kristina Launey, LSU Department of Physics & Astronomy. “Such large-scale calculations for nuclei beyond the lightest species are now feasible, with the use of supercomputers and interactions tied to the underlying physics of quarks and gluons. This was made possible by a diverse team of researcher, from some of the masters in nuclear physics, Draayer, Rowe, Wood, and Rosensteel, to a young emerging scientist Robert Baker, and scientists in computer science and physics Dytrych and Langr. Baker is currently a postdoctoral researcher at Ohio University, and worked on this study while being a PhD student at LSU, making significant contributions to novel calculations for the neon isotopes.”

The excitement of modern nuclear physics is its interdisciplinary nature and the use of a wide range of techniques and tools. The goal of the LSU Nuclear Theory Group is to provide an overall theoretical understanding of the structure of atomic nuclei at a fundamental level and predict properties of light and medium-mass nuclei that are key to pinpointing the origin, structure, and evolution of baryonic matter in the Universe. This is achieved by recognizing the symmetries that govern the nuclear dynamics and by employing state-of-the-art shell models with modern nucleon-nucleon interactions. This brings together techniques in many-body physics, group theory, and high-performance computing. Some of the research themes are ab-inito (from first principles) nuclear structure and reaction descriptions, phenomena ranging from pairing to clustering correlations and collective rotations, the limits of nuclear stability, nuclear astrophysics, and the weak interaction of nuclei.

Physical Review Letters (PRL), the world’s premier physics letter journal is the American Physical Society’s flagship publication. Since 1958 it has contributed to APS’s mission to advance and diffuse the knowledge of physics by publishing seminal research by Nobel Prize–winning and other distinguished researchers in all fields of physics.

Physics of Nuclei: Key Role of an Emergent Symmetry
T. Dytrych, K D. Launey, J P. Draayer, D J. Rowe, J. L. Wood, G. Rosensteel, C. Bahri, D. Langr, and R. B. Baker
Phys. Rev. Lett. 124, 042501



Mimi LaValle
LSU Department of Physics & Astronomy