Awards & Prizes

DATE2023.06.28 #Awards & Prizes

Professor Emeritus Takaharu Otsuka receives the Humboldt Prize


Professor Emeritus Takaharu Otsuka


Professor Emeritus Takaharu Otsuka of the Department of Physics has been awarded the Humboldt Prize (Humboldt-Forschungspreis). The Humboldt Prize is Germany's most prestigious academic award and is given to internationally renowned researchers who have made significant achievements in a wide range of research fields from the natural sciences to the humanities and who are expected to continue to push the boundaries of scientific knowledge.

Modern nuclear theory has a long history dating back to Professor Hideki Yukawa's research on nuclear forces produced by the pi meson exchange. The nuclear forces produced by meson exchange include a non-central force component called tensor force, which depends on the configuration of the nucleon spin. Clarifying the role of tensor forces in the nuclear structure has been a long-standing mystery. Professor Otsuka has developed a large-scale numerical method using the Monte Carlo shell model and has led innovative research on tensor forces. Specifically, he proposed a theory for the evolution of shell structure in exotic nuclei with an excess of protons and neutrons. According to the theory, the shell structure of nuclei changes due to tensor forces, predicting a new “magic number,” the number of protons or neutrons in a full shell. This shell evolution theory is now a guiding principle for RI (radioactive isotope) beam nuclear physics research around the world. As for his more recent contributions, Professor Otsuka has reconceptualized the ellipsoidal deformation of nuclei in terms of self-organization. In his proposed mechanism, the monopole-type force controls the competition between collective modes of motion and single-particle state energy, completely revolutionizing the interpretation of rotational bands taken for granted in many textbooks. Professor Otsuka's research is highly regarded internationally for pioneering a new paradigm in nuclear research and revising conventional wisdom.

Alexander von Humboldt Foundation website (English)

(Written by Professor Kenji Fukushima, Department of Physics)