Leonid Abramowich Bunimovich (born August 1, 1947) is a Soviet and American mathematician, who made fundamental contributions to the theory of Dynamical Systems, Statistical Physics and various applications.

His Master's proved that some classes of quadratic maps of an interval have an absolutely continuous invariant measure and strong stochastic properties.

Although the discovery of defocusing mechanism was just a part of Bunimovich's PhD thesis, he could not find any job after finishing graduate school thanks to antisemitic policies in the Soviet Union.

Notably, Bunimovich introduced and investigated hierarchical models of human populations,[8] which allowed to clarify laws of distribution of hereditary diseases and explain data on migration in industrial parts of developed countries.

In their previous paper was constructed the first infinite Markov partition for chaotic systems with singularities which allowed to transform this deterministic problem into probabilistic one.

Together with Ben Webb Bunimovich introduced and developed the theory of Isospectral transformations for analysis of multi-dimensional systems and networks.

[15][16] Together with Skums and Khudyakov Bunimovich discovered phenomenon of local immunodeficiency which demonstrates how viruses can cooperate to overcome an immune response of a human organism.

[17] It allowed to clarify numerous unexplained phenomena in evolution of the Hepatitis C and serves as new tool to study any disease with cross-immunoreactivity.