尼古拉·博戈柳博夫1909—1992

Nikolay Nikolayevich Bogolyubov (21 August 1909 – 13 February 1992) was a Soviet mathematician and theoretical physicist known for his significant contributions to quantum field theory, classical and quantum statistical mechanics, and the theory of dynamical systems; he was the recipient of the 1992 Dirac Medal for his works and studies.

Biography

Early life (1909–1921)

Nikolay Bogolyubov was born on 21 August 1909 in Nizhny Novgorod, Russia. His father, Nikolay Mikhaylovich Bogolyubov, was a Russian Orthodox priest and a teacher of theology, philosophy, and psychology at the Nizhny Novgorod Theological Seminary. His mother, Olga Nikolayevna, née Lyuminarskaya, was a music teacher.

Six months after Nikolay's birth, the family moved to Nezhin (present-day Ukraine), where his father taught him until 1913.

From 1913 to 1918, the family lived in Kiev. Nikolay was initially homeschooled. His father taught him the basics of arithmetic, as well as German, French, and English. At the age of six, he attended a preparatory class in the Kiev Gymnasium. However, he did not stay in the gymnasium for long, as the family moved to the village of Velyka Krucha. From 1919 to 1921, he studied at the Velykokruchanska seven-year school, which was the only educational institution he graduated from.

Kiev period (1921–1940)

The family soon moved to Kiev in 1921, where they continued to live in poverty as the elder Nikolay Bogolyubov only found a position as a priest in 1923. After finishing seven years of school, Bogolyubov independently studied physics and mathematics, and by the age of 14, he was already participating in the seminar of the Department of Mathematical Physics at Kiev University under the supervision of academician Dmitry Grave.

In 1924, at the age of 15, Bogolyubov wrote his first published scientific paper On the behavior of solutions of linear differential equations at infinity. In 1925, he entered Ph.D. program at the Academy of Sciences of the Ukrainian SSR under the supervision of the well-known contemporary mathematician Nikolay Krylov and obtained the degree of Candidate of Sciences (equivalent to a Ph.D.) in 1928, at the age of 19, with the doctoral thesis titled On direct methods of variational calculus.

Research

Fundamental works of Bogolyubov were devoted to asymptotic methods of nonlinear mechanics, quantum field theory, statistical field theory, variational calculus, approximation methods in mathematical analysis, equations of mathematical physics, theory of stability, theory of dynamical systems, and to many other areas.

He built a new theory of scattering matrices, formulated the concept of microscopical causality, obtained important results in quantum electrodynamics, and investigated on the basis of the edge-of-the-wedge theorem the dispersion relations in elementary particle physics. He suggested a new synthesis of the Bohr theory of quasiperiodic functions and developed methods for asymptotic integration of nonlinear differential equations which describe oscillating processes.

Mathematics and non-linear mechanics

In 1932–1943, in the early stage of his career, he worked in collaboration with Nikolay Krylov on mathematical problems of nonlinear mechanics and developed mathematical methods for asymptotic integration of non-linear differential equations. He also applied these methods to problems of statistical mechanics.

In 1937, jointly with Nikolay Krylov he proved the Krylov–Bogolyubov theorems.

In 1956, at the International Conference on Theoretical Physics in Seattle, USA (September, 1956), he presented the formulation and the first proof of the edge-of-the-wedge theorem. This theorem in the theory of functions of several complex variables has important implications to the dispersion relations in elementary particle physics.

Statistical mechanics

1939 Jointly with Nikolay Krylov gave the first consistent microscopic derivation of the Fokker–Planck equation in the single scheme of classical and quantum mechanics.

1945 Suggested the idea of hierarchy of relaxation times, which is significant for statistical theory of irreversible processes.

1946 Developed a general method for a microscopic derivation of kinetic equations for classical systems. The method was based on the hierarchy of equations for multi-particle distribution functions known now as Bogoliubov–Born–Green–Kirkwood–Yvon hierarchy.