The 97-year-old Mary Tsingou Menzel, who programmed a Los Alamos experiment that helped change modern physics, died at her Los Angeles home in August 2026. In the 1950s, she played a significant role in solving a complex physics problem using one of the earliest computers. But initially, she was recognised only in a footnote for her computational work.
The findings of the landmark experiment were published in 1955 but her name was not listed along with other authors. What was astonishing was that the experiment was named after three male scientists. More than half a century later, the American mathematician and computer programmer received wider recognition for her role in the breakthrough, which helped shape modern computational physics and the study of nonlinear systems.
Who was Mary Tsingou, and how did she join Los Alamos?
According to The New York Times, Mary Tsingou was born in Milwaukee, Wisconsin, on October 14, 1928, and was the younger of two daughters of Greek immigrant parents. Her family moved to Bulgaria during the Great Depression before returning to Milwaukee in 1940. From a very young age, she had a keen interest in mathematics. Later on, she earned a bachelor's degree from the University of Wisconsin in 1951 and initially hoped to become a high-school mathematics teacher but had to put a halt to her dreams due to limited teaching opportunities for women.
She subsequently learned that Los Alamos Scientific Laboratory was hiring women to perform mathematical calculations and joined the laboratory in 1952 as part of a group known as “human computers”, most of whom were women. Initially, her job was to perform calculations by hand or using basic calculating machines which made Mary Tsingou extremely disappointed. “It was pretty boring sitting there doing addition and subtraction,” she recalled in a 2020 publication by the federal research laboratory. But soon, her work moved beyond arithmetic when she was given the opportunity to program MANIAC I, an early electronic computer at Los Alamos.
How Mary Tsingou helped change physics
The New York Times reported that MANIAC I, Los Alamos’ early electronic computer, stood seven feet tall, weighed around 1,000 pounds and contained about 3,000 vacuum tubes. Programming it required translating instructions into punched tape. “You had to use what the machine recognized, which was only ones and zeros,” Tsingou said. “We typed the directions on a tape and put it in the machine.” Her skills led to a project with mathematician Stanislaw Ulam and physicists John Pasta and Enrico Fermi. They used the computer to simulate particles connected by springs, expecting energy to spread randomly through the system.
Mary Tsingou was born in Milwaukee, Wisconsin, on October 14, 1928
Instead, when Tsingou plotted the results, she found that the system followed structured patterns and periodically returned close to its original state.
The findings became known as the Fermi-Pasta-Ulam problem and helped advance nonlinear science and chaos theory, which explores how small changes in a system can lead to unpredictable outcomes.
Why was Mary Tsingou's contribution reduced to a footnote?
When the experiment's report was published in 1955, Tsingou was not named as an author. Her contribution appeared in a footnote: “We thank Miss Mary Tsingou for efficient coding of the problems and for running the computations on the Los Alamos MANIAC machine.”
Tsingou later explained the division of work: “They didn’t know anything about programming,” she told the Los Alamos publication. “They set up the equations, and I did all the programming.”
Tsingou's contribution gained wider attention in 2008, when French physicist Thierry Dauxois published an article in Physics Today titled “Fermi, Pasta, Ulam, and a Mysterious Lady.”
“Her programming of a 1950s computer was not a trivial task,” he wrote. “Why has her contribution received only a two-line acknowledgment?” The article helped bring recognition to Tsingou, and the experiment became more widely known as the Fermi-Pasta-Ulam-Tsingou problem (FPUT).
She also said she was not bothered by being left out of the original experiment's name. “I was just doing the job,” she said. “I was glad to get paid.”
Tsingou worked at Los Alamos for nearly 40 years, contributing to thermonuclear research and projects linked to the Strategic Defense Initiative, the Reagan-era missile defence programme popularly known as Star Wars.
She earned a master's degree in mathematics from the University of Michigan in 1955 and married Joseph Menzel in 1958. He died in 2022. Tsingou is survived by her daughters, Ann Menzel and Carol Menzel, eight grandchildren and three great-grandchildren.