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 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 for the "proton storage ring" in the
Star Wars program (the Strategic Defense Initiative), which was one of President Ronald Reagan's projects. She retired in 1991. ==Recognition==