In Memoriam: Noboru Takigawa (1943–2022)

Abstract

Noboru Takigawa passed away on 22 October 2022, at the age of 79. He was one of the world’s leaders in the field of low-energy heavy-ion reactions, and his approach influenced researchers worldwide. Born in Tsuchiura, Japan, on 1 July 1943, he received the Doctor of Science degree in 1971 from the University of Tokyo under the supervision of Akito Arima on studies of the cluster structure of 12C. In 1973, he started working on low-energy nuclear reactions at Hahn-Meitner institute. He took subsequent research associate positions at Techniche Universitat Munchen, Oxford University, IPN Orsay, and University of Munster, before he obtained a faculty position in 1979 at Tohoku University, Sendai, Japan. The scope of his research was very broad, and he worked on subjects as varied as the cluster structure of light nuclei; a semiclassical approach to heavy-ion elastic scattering; transport phenomena in deep inelastic collisions; quantum tunneling in fusion and fission; structure and reactions of neutron-rich nuclei; and electron screening on astrophysical nuclear reactions. His collaboration with David Brink on the application of WKB theory to optical potentials with three turning points has been widely recognized. The key point was the recognition that anomalous large-angle scattering in elastic scattering of alpha particles off heavy nuclei is due to an interference between barrier wave and internal wave. Around 1982, he started studying heavy-ion deep inelastic scattering and subbarrier fusion, and made many important contributions to that field. A common feature of these phenomena is that a system that is coupled to other degrees of freedom is largely influenced by those couplings. He was continuously interested in the physics of friction, dissipation, and fluctuation, and macroscopic quantum tunneling. He studied reactions of exotic nuclei soon after experiments with exotic nuclei started. In 1991, he showed that the halo structure of neutron-rich nuclei leads to reduction of the Coulomb barrier, which may result in enhancement of fusion cross-sections. In 1993, he used semiclassical theory to discuss the role of the breakup process of neutron-rich nuclei in subbarrier fusion, the idea of which has significantly influenced the field. In addition to research, he was keen on education. He had many good friends and colleagues worldwide, and his connection to them was very helpful for his former students who were employed worldwide. He often took his students with him when he traveled. This triggered a strong collaboration between Tohoku University and the experimentalists at the Australian National University regarding subbarrier fusion. He was an excellent host to many nuclear physicists whose visits to Sendai were intellectually rewarding, because it helped the guests not only to probe physics, but also to appreciate the depths of Japanese culture and language. He trained many students from around the world, including from Myanmar, Indonesia, Bangladesh, and the United States. He published a textbook, Fundamentals of Nuclear Physics, in 2013 (in Japanese) and in 2017 (in English). He always had a passion for physics. As his name suggests [his name means “to climb (Noboru) a falling river (Takigawa)”], he always promoted new physics with smart ideas and hard work. His hobby was listening to music, both classic and modern, such as opera and Japanese Enka. In his travels he often composed Haiku poetry, which he learned from his supervisor, Akito Arima. He was a kind and friendly person and many of us have many fond memories of him. He is certainly a big loss to us all.