# Mary Tsingou

Mary Tsingou (married name: Mary Tsingou-Menzel; born October 14, 1928) is an American physicist and mathematician of Greek-Bulgarian descent. She was one of the first programmers on the MANIAC computer at Los Alamos National Laboratory and is best known for having coded the celebrated computer experiment with Enrico Fermi, John Pasta, and Stanislaw Ulam. This experiment became an inspiration for the fields of chaos theory and scientific computing, and was a turning point in soliton theory.

## Life

Mary Tsingou was born in Milwaukee, Wisconsin, her Greek parents having moved to the United States from Bulgaria. In the aftermath of the Great Depression, the family left the US to spend several years in Bulgaria. In 1940, they returned to the States, where Tsingou attended high school and college. She graduated with a bachelor's degree in mathematics and education in 1951 from the University of Wisconsin. She then studied at the University of Michigan, receiving a master's degree in mathematics in 1955. In 1958, she married Joseph Menzel.

## Career

Tsingou joined the theoretical division of the Los Alamos National Laboratory, where she became one of the first programmers on the MANIAC. Besides working on weapons, the group also studied fundamental physics. Following Fermi's suggestion to analyze numerically the predictions of a statistical model of solids, Tsingou came up with an algorithm to simulate the relaxation of energy in a model crystal, which she implemented on the MANIAC. The analysis became known in the computational physics community as the Fermi–Pasta–Ulam–Tsingou problem (FPUT), and Tsingou's contributions have since been recognized. The result was an important stepping stone for chaos theory.
Early MANIAC programmers included Mary Hunsberger Kircher. She was interviewed in 2002 by the IEEE History Center. Mary Tsingou-Menzel was also interviewed in 2002.
After Fermi's death, James L. Tuck and Tsingou-Menzel repeated the original FPUT results and provided strong indication that the nonlinear FPUT problem might be integrable.
Tsingou-Menzel continued her computational career at Los Alamos. She was an early expert on Fortran. In the 1980s, she worked on calculations in the Star Wars program (the Strategic Defense Initiative). She retired in 1991.

## Recognition

The paper published by Los Alamos National Lab in 1955 earned recognition for Fermi, Pasta, and Ulam for its novel discoveries, with Tsingou being acknowledged in the footnote. It was not until 2008, when an article published in Physics Today called to rename the FPU problem to the FPUT problem to give her proper credit for her contribution. Subsequent publications referencing the FPUT problem reflect this change. In 2020, National Security Science magazine, published by Los Alamos National Laboratory, featured an article on Tsingou that included her commentary and historical reflections on the FPUT problem. The article was titled "We thank Miss Mary Tsingou" in reference to the acknowledgement that appeared on the title page of the original FPUT technical report from 1955.

## Publications

* J. L. Tuck; M. T. Menzel (1972). "The superperiod of the nonlinear weighted string (FPU) problem". Advances in Mathematics. 9 (3): 399–407. doi:10.1016/0001-8708(72)90024-2.
* Joseph J. Devaney, Albert G. Petschek, Mary Tsingou Menzel. On the Production of Heavy Uranium Isotopes in a Very High Density Fast Neutron Flux (accessed Dec. 2012). Los Alamos Scientific Laboratory of the University of California, 1958; 17 pages.