Ilya Lifshitz
Ilya Mikhailovich Lifshitz was a leading Soviet theoretical physicist, brother of Evgeny Lifshitz. He is known for his works in solid state physics, electron theory of metals, disordered systems, and the theory of polymers.Work
Together with Arnold M. Kosevich, Lifshitz established connection between the oscillation of magnetic characteristics of metals and the form of an electronic surface of Fermi from de Haas–van Alphen experiments.
Lifshitz was one of the founders of the theory of disordered systems.
He introduced some of the basic notions, such as self-averaging, and discovered what is now called Lifshitz tails and Lifshitz singularity.
In perturbation theory, Lifshitz introduced the notion of spectral shift function, which was later developed by Mark Krein.
