Atomic Physics2026-06-101 minarXiv:2606.12084expressAtomic Echo of Invisible ForcesAtomic nuclei are rarely perfect spheres. More often, they resemble a slightly squashed ball — the electric charge inside is unevenly distributed, and protons may shift a bit, creating a tiny 'pear-shaped' bulge.Bassam Nima·Mingyu Fan·Xubo Wang·Sen Wang·En Fu Zhou·Andrew M. Jayich·Jiang Ming Yao·Lan Cheng·Amar VuthaWolfgang PauliNMR spectroscopyStandard Model👍👎☆SimplePopularAdvanced