Yoichiro Nambu, a particle physicist at the University of Chicago whose mathematical description of the phenomenon known as spontaneous symmetry breaking helped explain the interaction of subatomic particles, contributed to the prediction of the Higgs boson, or “God particle,” and earned him the Nobel Prize in Physics in 2008, died on July 5 in Osaka, Japan. He was 94.

The University of Osaka, where he was a distinguished professor, announced his death on Friday.

In the late 1950s, Professor Nambu began investigating superconductivity, the process by which, at very low temperatures, electric current suddenly flows without any resistance.

He decided that spontaneous symmetry breaking, or SSB — the change from a symmetric to asymmetric state that scientists were just beginning to observe at the subatomic level — might better explain how substances become superconducting.

He developed a mathematical model to describe this phenomenon and quickly turned his attention to the world of subatomic particles. In 1960 he published a mathematical description of spontaneous symmetry breaking that became a cornerstone of the Standard Model, the unified theory that physicists use to explain three of the four fundamental forces in nature: strong, weak and electromagnetic. The fourth, gravity, has not yet been incorporated into the standard model.