Isaak Markovich Khalatnikov, Ukrainian-Russian physicist and academic

Isaak Markovich Khalatnikov (Russian: Исаа́к Ма́ркович Хала́тников; Ukrainian: Ісаа́к Ма́ркович Хала́тников; 17 October 1919 – 9 January 2021) was a leading Soviet theoretical physicist who has made significant contributions to many areas of theoretical physics, including general relativity, quantum field theory, as well as the theory of quantum liquids. He is well known for his role in developing the Landau-Khalatnikov theory of superfluidity and the so-called BKL conjecture in the general theory of relativity.