Jan M. Rost (born 1961) is a German theoretical physicist and director at the Max Planck Institute for the Physics of Complex Systems in Dresden heading the research department Finite Systems. He was awarded the status of Fellow in the American Physical Society, after nomination by the Division of Atomic, Molecular & Optical Physics in 2007, for seminal investigations of correlated doubly excited states, threshold fragmentation in few-body Coulombic systems and small clusters, pendular states of linear molecules, and for elucidating the role of correlation and relaxation in ultracold plasmas and Rydberg gases.