Arnold Theodore Nordsieck (January 5, 1911 – January 18, 1971) was an American theoretical physicist. He is best known for his work with Felix Bloch on the infrared problem in quantum electrodynamics. He developed the inertial electrostatic gyroscope (ESG) used as part of the inertial navigation system of nuclear submarines that allows them to remain underwater without having to surface to ascertain their location.
Nordsieck built a differential analyzer (a form of analog computer) in 1950 at the University of Illinois from $700 worth of surplus electronic parts left over from World War II. Copies became the first computers at the Lawrence Livermore National Laboratory and Purdue University.[4][5][6] In 1953 he developed the inertial electrostatic gyroscope (ESG), which was manufactured by Honeywell and other companies. It was used as part of the inertial navigation system of nuclear submarines, allowing them to travel underwater for months at a time without having to surface to ascertain their location.[7] He also proposed the Cornfield system, a computer-based decision-making system for the air defense of ships using radar. This was one of the first applications of computer technology for decision makings.[8][9] He was a 1955 Guggenheim Fellow.[10]
With B. L Hicks, Nordsieck use Monte Carlo methods to solve nonlinear Boltzmann equation for various non-equilibrium problems in gas dynamics in the 1960s.[11][12] He also published work on numerical mathematics.[13] Later Nordsieck worked for the General Research Corporation in Santa Barbara, California, where he was Head of physics.[14] He died in Santa Barbara on January 18, 1971.[15]