Toichiro Kinoshita

Toichiro Kinoshita

Amherst, MA - Toichiro Kinoshita, Goldwin Smith Professor of Physics, Emeritus, at Cornell University, passed away peacefully on March 23, 2023, at the age of 98.

Known to colleagues as "Tom," Kinoshita spent six decades at Cornell, where he was known for his extensive calculations in quantum electrodynamics, the theory most amenable to precise comparison with experimental measurements that thus tests the adequacy of current theory in explaining the universe.

"Quantum electrodynamics is a pinnacle of modern science," says Harvard physicist Andrew Strominger. "The experimental verification of its theoretical predictions beyond thirteen decimal places makes it the most accurate theory in the history of human thought. The first few digits are indicated on Julian Schwinger's headstone. Much of the remaining ones we owe to the insight and lifelong tenacity of Tom Kinoshita."

Each successive calculation was hugely more complex than the last. Kinoshita and his team pursued this work at super-computing facilities worldwide, inspired by advances in experimental precision. Hans Dehmelt, who with Wolfgang Paul was awarded the 1989 Nobel Prize in Physics for their breakthrough measurement of the electron anomalous magnetic moment, asked Kinoshita to join them at the Nobel ceremony, citing his "heroic" calculations.

Kinoshita traveled extensively to collaborate and to use computing facilities, notably at CERN (Geneva, Switzerland), KEK (Tsukuba, Japan), RIKEN (Wako, Japan). He was awarded fellowships from the Ford Foundation and the John Simon Guggenheim Memorial Foundation. He was editor and contributing author of Quantum Electrodynamics (1990, World Scientific), a definitive volume summarizing the field. His honors include the J.J. Sakurai Prize from the American Physical Society, the SUN-AMCO Medal from the International Union of Pure and Applied Physics, the Gian Carlo Wick Gold Medal, and the Toray Science and Technology Prize. He was a member of the National Academy of Sciences and a Fellow of the American Physical Society.

He remained active at the forefront of his field into his tenth decade, working particularly closely with former student Dr. Makiko Nio of Riken. His team's paper "Revised and Improved Value of the QED Tenth-Order Electron Anomalous Magnetic Moment" was published in 2017, and "Theory of the Anomalous Magnetic Moment of the Electron" in 2019.

Kinoshita, the eldest child of Tsutomu and Fumi Kinoshita, was born in in 1925 in the rural town of Kurayoshi on the Japan Sea coast of the main Japanese island of Honshu. Tsutomu, a younger son, eked out a modest living as a schoolteacher in a home lacking indoor plumbing and electricity. Toichiro was adopted by his paternal uncle as intended heir to his grandfather's sizeable land holdings, but he chose physics instead. Loving and excelling in the subject from a young age, he gained admission to the First Higher School in Tokyo and eventually to Tokyo Imperial University (now Tokyo University).

He entered college during World War II, narrowly avoiding military conscription as the war ended just prior to graduation. He began doctoral research at the same institution in 1947 under Kunihiko Kodaira, a mathematician who later became the first Japanese recipient of the Fields Medal. As part of a multi-institutional group working on quantum electrodynamics, Toichiro was unofficially advised by Shinichiro Tomonaga, who went on to share the Nobel Prize in Physics in 1965 with Richard Feynman and Julian Schwinger for the development of quantum electrodynamics.

In 1951, Kinoshita married Masako Matsuoka. He had just completed his PhD when he was invited by the American physicist J. Robert Oppenheimer in 1952 to the Institute for Advanced Study in Princeton, New Jersey, where he was joined a year later by Masako, who traveled by freighter from Japan to the US.

In 1958, following postdoctoral positions at Columbia and Cornell Universities, he joined the faculty at Cornell. He was promoted to Professor in 1963 and Goldwin Smith Professor in 1992. He continued his research at Cornell even after his retirement in 1995, until in 2014, he and Masako moved to Amherst, Massachusetts to live with their youngest daughter, Ray Mann, and her family. There he was welcomed as an emeritus Adjunct Professor at the University of Massachusetts Physics Department. His wife Masako passed way in August 2022.

Kinoshita was also devoted to his family. He was proud of his wife Masako's trailblazing work as a textile artist and researcher, and despite his upbringing in a patriarchal society, he expected nothing less from his three daughters, who all graduated from Harvard University for careers in particle physics, biomedicine, and architecture.

Kinoshita is survived by daughters and sons-in-law Kay Kinoshita and Alan Schwartz of Cincinnati, Ohio; June Kinoshita and Tod Machover of Waltham, Massachusetts; and Ray K. and Charles C. Mann of Amherst Massachusetts; sisters Michiko, Sachiko and Youko of Tokyo, Japan; and six grandchildren, Maya Schwartz, Eito Schwartz, Hana Machover, Noa Machover, Emilia Mann, and Schuyler Mann. There will be a private visitation for family and friends on April 22 at 982 East Pleasant Street in Amherst, Massachusetts. A celebration of Toichiro and Masako's lives will take place on August 19th in Ithaca, New York.