Grishchuk Leonid Petrovich General data:
16.08.1941 - 13.09.2012
Place of birth: Zhytomyr city, Zhytomyr region, Ukrainian SSR
Studied in: M. V. Lomonosov Moscow State University (1958-1964);
Key interests: theoretical astronomy, astrophysics, cosmology, general theory of relativity, theoretical astrophysics, astronomy. PhD Thesis: On the problem of singularities in solutions of the Einstein equations (1967 P. K. Sternberg State Astronomical Institute, M. V. Lomonosov Moscow State University); ScD Thesis: Gravitational waves, their physical properties and astrophysical manifestations (1977 P. K. Sternberg State Astronomical Institute, M. V. Lomonosov Moscow State University);
Biography:
He was born August 16, 1941 in Zhytomyr city of Zhytomyr region of the Ukrainian SSR. He was the youngest child into a large family: he had four older brothers and sister.
During 1948-1956 he studied at the secondary school of Zhytomyr. After graduating from high school with a gold medal, the young man in 1958 entered the Physics Department of the M. V. Lomonosov Moscow State University, who graduated in 1964. He first studied at the department of physics, and from the middle of the first year passed to the department of astronomy.
From 1967 he worked at the P. K. Sternberg State Astronomical Institute M. V. Lomonosov Moscow State University, and later he worked for many years as a senior researcher of the department of relativistic astrophysics, during 1987-1990 he was the head of the department.
In 1967, he defended his PhD thesis "On the problem of singularities in the solutions of Einstein's equations" to the P. K. Sternberg State Astronomical Institute of M. V. Lomonosov Moscow State University, under the direction of A. L. Zelmanov. In it he proved the theorem on the singularity of solutions of the equations of the general theory of relativity for dust matter on time-like hypersurfaces, more precisely he proved the first constructive refutation of the proposition that the solutions of the general theory of relativity equations (in vacuum or in the presence of matter) cannot have physical singularity.
After defending his dissertation, the scientist was invited to the University of Warsaw. The result of this trip was a study together with well-known Polish cosmologist M. Demiansky about the effect of rotation on the dynamics of a homogeneous anisotropic Universe.
From Einstein's field equations he derived an equation describing gravitational waves in the early Universe and showed that this equation is not conformally invariant. On this basis, he made the prediction that the Big Bang should generate a rich spectrum of relic gravitons.
In 1977 he defended his doctoral dissertation "Gravitational waves of their physical properties and astrophysical manifestations" at the P. K. Sternberg State Astronomical Institute M. V. Lomonosov Moscow State University.
In the 1970s, he worked together with V. B. Braginsky, A. G. Doroshkevich, Ya. B. Zeldovich, I. D. Novikov and M. V. Soot by the theory of interaction of gravitational waves with electromagnetic waves.
Together with J. B. Zel'dovich developed the theory of fluctuation of the curvature of the Universe in the early epochs on scales beyond the then horizon. This phenomenon was called the Grishchuk-Zeldovich effect. The working hypothesis was that as the universe expands, these fluctuations may manifest themselves below the horizon. However, verification of this phenomenon from the distribution of a large number of quasars with z = 3 ÷ 4.5 from the SDSS catalog did not confirm the presence of asymmetry in the two hemispheres.
In 1979, he substantiated the inevitability of the generation of gravitational waves in the early stages of the expansion of the universe. He showed that the equations for gravitational waves are not conformally invariant, therefore, the primordial gravitons had to be born in huge numbers. He substantiated the fundamental concept according to which quantum-mechanical generation of cosmological perturbations can be explained by means of compressed quantum states. Together with the students he developed field formulations of equations of general relativity on an arbitrarily distorted background, worked on modified theories of massive gravity. Together with V. A. Belinsky, I. M. Khalatnikov and Ya. B. Zel'dovich received proof that "inflation trajectories" for a dynamic system, including scalar and gravitational fields, are attracted in phase space.
Since 1990 to 1991, he worked under a scientific exchange agreement at Boulder University in Colorado, USA, and since 1992 to 1993 worked at St. Louis University in Washington, DC, and since 1994 to 2009 Professor at Cardiff University in the UK.
In 2006 the scientist together with A.G. Polnarev and D. Baskaran have developed a new method for detecting cosmological gravitational waves by correlating anisotropy of E-polarization in the background relic radiation.
After retiring in 2009, the scientist continued to conduct scientific work until his untimely death.
He died on 13 September 2012 in Cardiff, UK, after a serious illness.
The area of scientific interest of the scientist is the theory of gravity, exact solutions of the equations of the general theory of relativity, quantum gravity, generation and registration of cosmological and astrophysical gravitational waves. He is the author of more than 200 scientific papers.
Together with the students, the scientist justified the fundamental concept according to which quantum-mechanical generation of cosmological perturbations in the early universe can be explained by "compressed" quantum states, leading to the phenomenon of standing waves and modulation of individual peaks in the fluctuation range of fluctuation called the Sakharov oscillations).
Together with S. M. Kopeykin he obtained relativistic equations of motion for compact bodies (neutron stars, black holes), taking into account the recoil response when emitted by gravitational waves.
He, in conjunction with Zel'dovich, showed that data on the magnitude of the quadrupole component in the fluctuations in the cosmological microwave background radiation impose strict restrictions on the magnitude of the inhomogeneity and anisotropy of the universe on length scales, hundreds of times greater than the magnitude of the globe.
In 1990, together with B. Bertotti, a strong principle of equivalence was analyzed and it was concluded that, in general relativity, this principle, under certain constraints, affects system parameters, unlike other metric theories.
In the early 2000s he co-authored with S.V. Groundhog offered a variant of the massive theory of gravity (modification of the general theory of relativity), where mass, unlike the already known analogous theories, have two types of gravitons: ordinary, with spin 2, and scalar, with spin 0. The authors showed that in their theory at the assumption of a very small mass of gravitons, m 0 = 10-65 g, there are objects such as "bare singularities" instead of the usual black holes with event horizons; the normal Universe expansion mode is replaced by an oscillating Universe.
Under the leadership of L.P. Grischuk defended more than ten candidate and doctoral
dissertations. He was a member of the editorial board of the journal Uspekhi Physical Nauk and a number of scientific societies.
Main publications:
1. Грищук Л.П., Зельдович Я.Б. Длинноволновые возмущения в фридмановской Вселенной и анизотропия фонового излучения//Soviet Astronomy, 22, 125, 1978
2. Л. П. Грищук, Реликтовые гравитационные волны и космология//УФН, 2005,том 175, номер 12, 1289–1303
3. Л. П. Грищук, В. М. Липунов, К. А. Постнов, М. Е. Прохоров, Б. С. Сатьяпракаш, Гравитационно-волновая астрономия: в ожидании первого зарегистриро-ванного источника//УФН, 2001, том 171, номер 1, 3–59
4. В. Л. Гинзбург, М. С. Аксентьева, В. С. Бескин, Л. П. Грищук, Ю. В. Гуляев, И. М. Дремин, Г. Р. Иваницкий, А. А. Каплянский, Д. Н. Клышко, Г. Н. Кулипанов, Л. Б. Окунь, Л. П. Питаевский, В. И. Ритус, В. А. Рубаков, Б. М. Смирнов, В. Д. Шафранов, И. A. Яковлев «Журналу „Успехи физических наук“ — 80 лет» Выпуск 1, 1999, том 169, 3–6
Sources:
1 Алексей Гэинэ Что-то не так на Украине
2 Комберг Б.В., Репин С.В. Звездные Острова Вселенной с релятивистскими ”гейзерами“ в центрах. (Галактики на ”рабочем столе“.) – М.: Янус-К, 2014. – 312 с.-С.166, 232-233
3 АСТРОКУРЬЕР, № 9 Сентябрь 2016 г.
4 ru.wikipedia.org
