Berni Julian Alder, theoretical physicist and inventor of molecular dynamics, 1925–2020 (original) (raw)

2021, Proceedings of the National Academy of Sciences of the United States of America

Berni Julian Alder, one of the leading figures in the invention of molecular dynamics simulations used for a wide array of problems in physics and chemistry, died on September 7, 2020. His career, spanning more than 65 years, transformed statistical mechanics, many body physics, the study of chemistry, and the microscopic dynamics of fluids, by making atomistic computational simulation (in parallel with traditional theory and experiment) a new pathway to unexpected discoveries. Among his many honors, the CECAM prize, recognizing exceptional contributions to the simulation of the microscopic properties of matter, is named for him. He was awarded the National Medal of Science by President Obama in 2008. Alder was born to Ludwig Adler and Otillie née Gottschalk in Duisburg, Germany on September 9, 1925. Alder's father Ludwig was a chemist who worked in the German aluminum industry. When the Nazis came to power in 1933, Alder, his parents, elder brother Henry, and twin brother Charles fled to Zurich, Switzerland. In 1941, they further emigrated to the United States (becoming "Alders" in the process), where they settled in Berkeley, California. From then on, he and his family lived and worked in the Bay Area, which they considered their "slice of heaven." Alder completed his senior year of high school there and then did his undergraduate studies at the University of California, Berkeley. Alder's education was interrupted by his service in the US Navy as a radar technician in the Pacific Theater. Later, he and his wife Esther raised their two sons and a daughter in the Bay Area community of El Cerrito. As a Berkeley undergraduate, Alder's mentor was the great chemist Joel Hildebrand, who influenced his early thinking about chemical systems. Later, circa 1951, as a student of J. G. Kirkwood at the California Institute of Technology, Alder began to explore the idea of Monte Carlo sampling applied to atomistic systems. This early work brought him to the attention of Edward Teller who, with Nicolas Metropolis, Marshall Rosenbluth, Arianna Rosenbluth, and Augusta Teller, had invented the famous "Metropolis" Monte Carlo