Yakov Zeldovich

Yakov Borisovich Zeldovich ForMemRS (Belarusian: Я́каў Бары́савіч Зяльдо́віч, Russian: Я́ков Бори́сович Зельдо́вич; 8 March 1914 – 2 December 1987), also known as YaB, was a Soviet physicist, who is known for his prolific contributions in cosmology and the physics of thermonuclear and hydrodynamical phenomena.

From 1943, Zeldovich played a crucial role in the development of the Soviet Union's nuclear bomb project. In 1963, he returned to academia to embark on pioneering contributions on the fundamental understanding of the thermodynamics of black holes and expanding the scope of cosmology.

Biography

Early life and education

Yakov Zeldovich was born into a Belarusian Jewish family in his grandfather's house in Minsk, Belarusian region in Russia, on March 8 1914. However, in mid-1914, the Zeldovich family moved to St. Petersburg. They resided there until August 1941, when the family was evacuated together with the faculty of the Institute of Chemical Physics to Kazan to avoid the Axis Invasion of the Soviet Union. They remained in Kazan until the summer of 1943, when Zel'dovich moved to Moscow.

His father, Boris Naumovich Zeldovich, was a lawyer; his mother, Anna Petrovna Zeldovich (née Kiveliovich), a translator from French to Russian, was a member of the Writer's Union. Despite being born into a devoted and religious Jewish family, Zel'dovich was an "absolute atheist".

Zeldovich was an autodidact. He was regarded as having a remarkably versatile intellect, and during his life he explored and made major contributions to a wide range of scientific endeavors. From a given opportunity in May 1931, he secured an appointment as a laboratory assistant at the Institute of Chemical Physics of the USSR Academy of Sciences, and remained associated with the institute for the remainder of his life. As a laboratory assistant, he received preliminary instructions on the topics involved in the physical chemistry and built up his reputation among his seniors at the Institute of Chemical Physics.

From 1932 to 1934, Zeldovich attended the undergraduate courses on physics and mathematics at the Leningrad State University (now St. Petersburg State University), and later attended the technical lectures on introductory physics at the Leningrad Polytechnic Institute (now Peter the Great St. Petersburg Polytechnic University).

In 1936, he was successful in his candidacy for the Candidate of Science degree (a Soviet equivalent of PhD), having successfully defended his dissertation on the topic of the "adsorption and catalysis on heterogeneous surfaces". The centrality of his thesis focused towards the research on the Freundlich (or classical) adsorption isotherm, and Zeldovich discovered the theoretical foundation of this empirical observation.

In 1939, Zeldovich prepared his dissertation based on the mathematical theory of the physical interpretation of nitrogen oxidation, and successfully received the Doctor of Science on Physmatics when it was reviewed by Aleksandr A. Freiman. Zel'dovich discovered its mechanism, known in physical chemistry as the thermal NO x mechanism or Zel'dovich mechanism.

Soviet atomic bomb program

Zeldovich is regarded as one of the secret principals of the Soviet nuclear weapons project, and his travels abroad were highly restricted to the Eastern Europe under close security by the Soviet Union. Soon after the discovery of nuclear fission by German chemist Otto Hahn in 1939, Russian physicists began investigating the spectrum of physics of fission and began hosting the seminars on that topic, extending the invitation to Igor Kurchatov and Yulii Khariton in 1940.

In May 1941, Zeldovich worked with Yulii Khariton in achieving the constructed theory on theory of the kinetics of nuclear reactions in the presence of the critical conditions. The work of Khariton and Zeldovich was extended towards the theories of ignition, combustion and detonation, that accounted for features not previously explained or correctly predicted features that had not yet been observed. The modern theory of detonation accordingly is called ZND theory (Zeldovich-von Neumann-Dohring), and engaged the tedious work on fast neutron calculations but the work had delayed due to the German invasion of Soviet Union that disrupted the findings which were marked as classified in June 1941. In 1942, Zeldovich was relocated to Kazan where he was tasked by the People's Commissariat of Munitions to carry out the work on the conventional gun powders to be supplied to the Soviet Army while Khariton was asked to design the new types of conventional weaponry.

In 1943, Joseph Stalin decided to launch the arms build-up of nuclear weapons, having given the charge to Igor Kurchatov who requested Stalin to relocate Zeldovich and Khariton to Moscow for nuclear weapons program. Zeldovich joined Igor Kurchatov's small team at the secretive laboratory in Moscow to launch the work on the nuclear combustion theory and became a head of the theoretical department at the Arzamas-16 in 1946.

Zeldovich developed a scientific report with Isaak Gurevich, Isaak Pomeranchuk, and Khariton on the feasibility of releasing energy through nuclear fusion triggered by an atomic explosion and presented it to Igor Kurchatov. Zeldovich had benefitted from physical and technical knowledge provided by German physicist Klaus Fuchs and American physicist Theodore Hall, who had worked on the American Manhattan Project to develop nuclear weapons.

In 1949, Zeldovich led a team of physicists that conducted the first nuclear test, the RDS-1, based roughly on the American design obtained through the atomic spies in the United States, though he continued his fundamental work on explosive theory. Zeldovich then began working on modernizing the successive designs of the nuclear weapon and initially conceived the idea of hydrogen bomb to Andrei Sakharov and others. In the course of his work on nuclear weapons, Zeldovich did ground-breaking work in radiation hydrodynamics, and the physics of matter at high pressure. Between his younger colleagues in Sarov, which worked in this area was Mihail Aleksandrovich Podurets, which is known also for his contribution to the theory of gravitational collapse

Between 1950 and 1953, Zeldovich performed calculations necessary for the feasibility of the hydrogen bomb that were verified by Andrei Sakharov, although the two groups worked in parallel on the development of the thermonuclear fusion. However, it was Sakharov that radically changed the approach to thermonuclear fusion, aided by Vitaly Ginzburg in 1952. He remained associated with the nuclear testings while heading the experimental laboratories at Arzamas-16 until October 1963, when he left for the academia.

Academia and cosmology

In 1952, Zeldovich began work in the field of elementary particles and their transformations. He predicted the beta decay of a pi meson. Together with S. Gershtein he noticed the analogy between the weak and electromagnetic interactions, and in 1960, he predicted the muon catalysis (more precisely, the muon-catalysed dt-fusion) phenomenon. In 1977, Zeldovich together with Fyodor Shapiro was awarded the Kurchatov Medal, the highest award in nuclear physics of the USSR. The citation was "for prediction of characteristics of ultracold neutrons, their detection and investigation". He was elected academician of the USSR Academy of Sciences on 20 June 1958. He was a head of division at the Institute of the Applied Mathematics of the USSR Academy of Sciences from 1965 until January 1983.

In early 1960s, Zeldovich started working in astrophysics and physical cosmology. In 1964, he and independently Edwin Salpeter were the first to suggest that accretion discs around massive black holes are responsible for the huge amounts of energy radiated by quasars. From 1965, he was a professor at the Department of Physics of the Moscow State University and a head of the division of Relativistic Astrophysics at the Sternberg Astronomical Institute. In 1966, he and Igor Novikov was the first to propose searching for black hole candidates among binary systems in which one star is optically bright and X-ray dark and the other optically dark but X-ray bright (the black hole candidate).

Zeldovich worked on the theory of the evolution of the hot universe, the properties of the microwave background radiation, the large-scale structure of the universe, and the theory of black holes. He predicted, with Rashid Sunyaev, that the cosmic microwave background should undergo inverse Compton scattering. This is called the Sunyaev-Zeldovich effect, and measurements by telescopes such as the Atacama Cosmology Telescope and the South Pole Telescope has established it as one of the key observational probes of cluster cosmology. Zeldovich contributed sharp insights into the nature of the large scale structure of the universe, in particular, through the use of Lagrangian perturbation theory (the Zeldovich approximation) and the application of the Burgers' equation approach via the adhesion approximation.

Black hole thermodynamics

Zeldovich played a key role in developing the theory of black hole evaporation due to Hawking radiation. Zeldovich and Charles Misner concomitantly predicted the possibility of particles generation by rotating Kerr black holes in 1971, 1972. Before, In 60-th Zeldovich predicted that Kerr black holes should split emission lines of photons as in a Zeeman effect During Stephen Hawking's visit to Moscow in 1973, Soviet scientists Zeldovich and Alexei Starobinsky showed Hawking that, according to the quantum mechanical uncertainty principle, rotating black holes should create and emit particles.

Family

With his wife, Varvara Pavlovna Konstantinova, Yakov Zeldovich had a son and two daughters who were also physicists: son – Boris Yakovlevich Zeldovich; daughters – Olga Yakovlevna Zeldovich and Marina Yakovlevna Zeldovich.

Zeldovich also had a daughter, Annushka, with O.K. Shiryaeva.

Publications

Books

Awards and honors

Igor Kurchatov called him a "genius" and Andrei Sakharov named him "a man of universal scientific interests." Stephen W. Hawking once said to Zel'dovich: "before I met you, I believed you to be a 'collective author', like Bourbaki."