Ezechiel Godert David "Eddie" Cohen (January 16, 1923[1] – September 24, 2017) was a Dutch–American physicist and Professor Emeritus at The Rockefeller University.
He is the editor of a number of books, including the series Fundamental Problems in Statistical Mechanics, I–VI, which contains an account of the developments in his field over almost 45 years.
Early in his career, Cohen predicted the possibility of an incomplete phase separation in liquid helium mixtures at very low temperatures that was later discovered experimentally, leading to the design of the helium dilution refrigerator, one of the basic low-temperature instruments available.
This discovery effectively closed off one entire line of research in nonequilibrium statistical mechanics.
Later with Denis Evans and Gary Morriss in 1990 he proved that for certain classes of thermostatted nonequilibrium steady states the relevant transport coefficient has a simple relation to the sum of the largest and smallest Lyapunov exponents describing the trajectory of the N-particle steady state system in phase space.
This mixture of random and deterministic features has led to a number of new types of particle diffusion, which can evolve suddenly to propagation.