  Exact symmetry and symmetry-breaking phenomena play a key role in providing a
better understanding of the physics of many-particle systems, from quarks and
atomic nuclei, to molecules and galaxies. In atomic nuclei, exact and dominant
symmetries such as rotational invariance, parity, and charge independence have
been clearly established. However, even when these symmetries are taken into
account, the structure of nuclei remains illusive and only partially
understood, with no additional symmetries immediately evident from the
underlying nucleon-nucleon interaction. Here, we show through ab initio
large-scale nuclear structure calculations that the special nature of the
strong nuclear force determines additional highly regular patterns in nuclei
that can be tied to an emergent approximate symmetry. We find that this
symmetry is remarkably ubiquitous, regardless of its particular strong
interaction heritage, and mathematically tracks with a symplectic group.
Specifically, we show for light to intermediate-mass nuclei that the structure
of a nucleus, along with its low-energy excitations, respects symplectic
symmetry at about 70-80% level, unveiling the predominance of only a few
equilibrium shapes, deformed or not, with associated vibrations and rotations.
This establishes the symplectic symmetry as a remarkably good symmetry of the
strong nuclear force, in the low-energy regime. This may have important
implications to studies in astrophysics and neutrino physics that rely on
nuclear structure information, especially where experimental measurements are
incomplete or not available. A very important practical advantage is that this
new symmetry can be utilized to dramatically reduce computational resources
required in ab initio large-scale nuclear structure modeling. This, in turn,
can be used to pioneer predictions, e.g., for short-lived isotopes along
various nucleosynthesis pathways.
