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BIOGRAPHIES OF GREAT SCIENTISTS
Landau Lev Davidovich. Biography of a scientist
Directory / Biographies of great scientists
Lev Davidovich Landau was born on January 9 (22), 1908 in the family of David Lvovich and Lyubov Veniaminovna (Garkavi) Landau in Baku. His father was a well-known petroleum engineer who worked in the local oil fields, and his mother was a doctor. She was engaged in physiological research. Landau's older sister became a chemical engineer. “I wasn’t a child prodigy,” the scientist recalled about his school years. “While studying at school, I didn’t get marks above triples in essays. I was interested in mathematics. at thirteen, integrate." Lev Davidovich was modest. He graduated from high school when he was only thirteen years old. His parents considered that he was too young for a higher educational institution and sent him for a year to the Baku Economic College. In 1922, Landau entered Baku University, where he studied physics and chemistry; two years later he transferred to the physics department of Leningrad University. By the time he was 19, Landau had published four scientific papers. One of them was the first to use the density matrix, a now widely used mathematical expression for describing quantum energy states. After graduating from the university in 1927, Landau entered the graduate school of the Leningrad Institute of Physics and Technology, where he worked on the magnetic theory of the electron and quantum electrodynamics. He greedily pounces on physical literature, reads still "hot" works on quantum mechanics, which at that time is experiencing a stormy birth, all articles that have just come out from the pen of their authors - the creators of the physics of the microworld. Landau was by no means alone in those years, and he did not form his scientific outlook alone. Next to him and at a fairly close level were other young theoreticians. It was a close company united by common interests. Three people set the tone in it: Landau, Gamov and Ivanenko, then Bronstein joined them. They called themselves a "jazz band". It was then that Landau became Dau; He carried this name throughout his life. That was the name of him by all people who were at all close to him, including his students. From 1929 to 1931 Landau was on a scientific mission in Germany, Switzerland, England, the Netherlands and Denmark. There he met with the founders of the then new quantum mechanics, including Werner Heisenberg, Wolfgang Pauli. Landau spent most of his time in Copenhagen with Niels Bohr. The Bohr Institute was a true world center of theoretical physics, a "physical Mecca" where theorists from all over the world came together. There was a lot of hard work going on there. From those years, forever, until the end of his life, his friendship with Bor and love for Bor remained. And each of their meetings will be a holiday for Landau. While abroad, Landau conducted important research on the magnetic properties of free electrons and, together with Ronald F. Peierls, on relativistic quantum mechanics. These works put him forward among the leading theoretical physicists. He learned how to deal with complex theoretical systems, and this skill was useful to him later, when he began research in low-temperature physics. In 1931, Landau returned to Leningrad, but soon moved to Kharkov, which was then the capital of Ukraine. There, Landau becomes the head of the theoretical department of the Ukrainian Institute of Physics and Technology. At the same time, he heads the departments of theoretical physics at the Kharkov Mechanical Engineering Institute and at Kharkov University. In 1934, the Academy of Sciences of the USSR awarded him the degree of Doctor of Physical and Mathematical Sciences without defending a dissertation, and the following year he received the title of professor. In Kharkov, Landau publishes works on such diverse topics as the origin of stellar energy, the dispersion of sound, the transfer of energy in collisions, the scattering of light, the magnetic properties of materials, superconductivity, the phase transitions of substances from one form to another, and the movement of streams of electrically charged particles. This gives him a reputation as an unusually versatile theorist. Landau's work on electrically interacting particles turned out to be useful later, when the physics of plasma arose - hot, electrically charged gases. Borrowing concepts from thermodynamics, he expressed many innovative ideas regarding low-temperature systems. Landau's works are united by one characteristic feature - the virtuoso application of the mathematical apparatus for solving complex problems. Landau made a great contribution to quantum theory and to studies of the nature and interaction of elementary particles. The unusually wide range of his research, covering almost all areas of theoretical physics, attracted many highly gifted students and young scientists to Kharkov, including Evgeny Mikhailovich Lifshitz, who became not only Landau's closest collaborator, but also his friend. The school that grew up around Landau turned Kharkov into a leading center of Soviet theoretical physics. It is striking that a strictly scientific school was born in the mid-thirties, when its founder was not yet thirty, and he often turned out to be the same age as his followers. That is why in this school everyone was with each other, and many with the teacher on "you". Landau's school was probably the most democratic community in Russian science. Anyone could join it - from a doctor of sciences to a schoolboy, from a professor to a laboratory assistant. The only thing that was required of the applicant was to successfully hand over to the master himself or his trusted employee what was called the LANDAU THEORMINIMUM. Passing the Landau theoretical minimum was akin to the tests of climbers when climbing the "eight-thousander". Yevgeny Livshits said that starting from 1934, Landau himself began to keep a list of names of those who passed this test. By January 1962, this grandmaster list included only forty-three names. But ten of these names already belonged to academicians and twenty-six to doctors of science! To help his students, Landau in 1935 created a comprehensive course in theoretical physics, published by him and Lifshitz in the form of a series of textbooks, the contents of which were revised and updated by the authors over the next twenty years. These textbooks, translated into many languages, are deservedly considered classics all over the world. But Landau and his comrades did not live by one job. In their free time, they played tennis, composed songs, staged performances, arranged costume parties, and generally had fun in every possible way. As in Leningrad, young people gave each other nicknames. Landau was called "Skinny Lion" (later he began to talk about himself that he did not have a physique, but a body subtraction). And yet he had a certain grace. And even skill. Not bad, although funny, holding a racket not according to the rules, he played tennis. From Kharkov, changes began in Landau's personal fate. He met Concordia Drobantseva, whose absolute beauty captivated him at first sight, and fell in love with her. In 1937, a few years later, Kora Drobantseva, a process engineer at a confectionery factory, moved to Moscow and became Landau's wife. In 1946, their son Igor was born, who later worked as an experimental physicist at the same Institute for Physical Problems, in which his father did so much. Landau despised those who set out to turn science over without fail and exalt themselves in it, as well as any careerists and opportunists from science. Dau was an amazingly clean person, says O. N. Trapeznikova. Therefore, much in his behavior cannot be measured by ordinary standards. He fought the "bison", hated the "gnats". At the same time, Trapeznikova recalls, when she asked what quality he values most in people, Landau answered without hesitation: "Kindness." The conflicts that Landau and some of his friends and students entered into began to turn into big troubles, the matter took on a serious turn. In the end, the question arose of moving to another city. In 1937, Landau, at the invitation of Pyotr Kapitsa, headed the department of theoretical physics at the newly created Institute for Physical Problems in Moscow. But the following year, Landau was arrested on false charges of spying for Germany. Only the intervention of Kapitsa, who appealed directly to the Kremlin, made it possible to secure Landau's release. When Landau moved from Kharkov to Moscow, Kapitsa's experiments with liquid helium were in full swing. Gaseous helium becomes liquid when cooled to a temperature below 4,2 K (in degrees Kelvin, the absolute temperature is measured, measured from absolute zero, or from a temperature of minus 273,18 ° C). In this state, helium is called helium-1. When cooled to temperatures below 2,17 K, helium turns into a liquid called helium-2, which has unusual properties. Helium-2 flows through the smallest holes with such ease, as if it had no viscosity at all. It rises along the wall of the vessel, as if it were not affected by gravity, and has a thermal conductivity hundreds of times greater than that of copper. Kapitsa called helium-2 a superfluid liquid. But when tested by standard methods, for example, by measuring the resistance to torsional vibrations of a disk at a given frequency, it turned out that helium-2 does not have zero viscosity. Scientists have suggested that the unusual behavior of helium-2 is due to effects related to the field of quantum theory, and not classical physics, which appear only at low temperatures and are usually observed in solids, since most substances freeze under these conditions. Helium is an exception - if it is not subjected to very high pressure, it remains liquid down to absolute zero. In 1938, Laszlo Tissa suggested that liquid helium is actually a mixture of two forms, helium-1 (normal liquid) and helium-2 (superfluid). When the temperature drops to near absolute zero, helium-2 becomes the dominant component. This hypothesis made it possible to explain why different viscosities are observed under different conditions. Landau explained superfluidity using a fundamentally new mathematical apparatus. While other researchers applied quantum mechanics to the behavior of individual atoms, he treated the quantum states of a volume of liquid in much the same way as if it were a solid. Landau put forward a hypothesis about the existence of two components of motion, or excitation: phonons, which describe the relatively normal rectilinear propagation of sound waves at low values of momentum and energy, and rotons, which describe rotational motion, i.e., a more complex manifestation of excitations at higher values of momentum and energy . The observed phenomena are due to the contributions of phonons and rotons and their interaction. Liquid helium, Landau argued, can be thought of as a "normal" component immersed in a superfluid "background." In an experiment on the outflow of liquid helium through a narrow slit, the superfluid component flows while phonons and rotons collide with the walls that hold them. In the experiment with torsional vibrations of the disk, the superfluid component has a negligible effect, while phonons and rotons collide with the disk and slow it down. The ratio of the concentrations of the normal and superfluid components depends on the temperature. Rotons dominate at temperatures above 1 K, phonons - below 0,6 K. Landau's theory and its subsequent improvements made it possible not only to explain the observed phenomena, but also to predict other unusual phenomena, for example, the propagation of two different waves, called the first and second sound, and having different properties. The first sound is ordinary sound waves, the second is a temperature wave. Landau's theory helped to make significant progress in understanding the nature of superconductivity. In the summer of 1941 the institute was evacuated to Kazan. There, like other employees, Landau gave his strength, first of all, to defense tasks. He built theories and made calculations of the processes that determine the combat effectiveness of weapons. In 1945, when the war ended, three articles by Landau devoted to the detonation of explosives appeared in the Reports of the Academy of Sciences. After the end of the war and until 1962, he worked on solving various problems, including studying a rare helium isotope with an atomic mass of 3 (instead of the usual mass of 4), and predicting for it the existence of a new type of wave propagation, which he called "zero sound" . Note that the speed of the second sound in a mixture of two isotopes tends to zero at absolute zero temperature. Landau also took part in the creation of the atomic bomb in the Soviet Union. Once, in the fifties, Corresponding Member Artemy Alikhanyan told an almost implausible story about Dau. Visiting him, he complained that at the Aragap station of cosmic rays he and his collaborators could not manage to obtain one energy formula, which is very important for cosmos, consistent with experiment. After asking two or three questions, Landau said: “You play here with my Garik, and I’ll go up to my room for a minute ...” He returned a quarter of an hour later ... On a sheet scribbled in childishly clear scribbles, the desired formula was deduced! .. The intensity of Landau's hard and fruitful work did not weaken at all until the fateful day. On January 7, 1962, a car accident occurred on the highway on the way to Dubna ... Nobody was to blame. Worst weather. Black ice. The girl ran across the road. The abruptly braked passenger car skidded sharply. The blow of the oncoming truck came from the side, and the passenger sitting at the door experienced all its force. The first Sunday morning of the new year was marked by a tragic event for Russian and world science. The physicists called back, stunned by the rumors about the misfortune with Academician Landau. Everyone checked the veracity of what had happened. For all, the brief sounded absurd: "Dow unconscious!" He was consciousness embodied. Creative consciousness. But a miracle happened - Landau survived! And this miracle was created together with the doctors of physics. Pilots of international aviation joined the relay race of transferring urgently needed drugs to "Mr. Landau" in Moscow. Medicines flew from America, England, Belgium, France, Czechoslovakia. Academicians Nikolai Semyonov and Vladimir Engelhardt on the very first ill-fated Sunday, January 7, synthesized and sterilized a substance against cerebral edema. The finished ampoule from Leningrad was ahead of them. But what was the active impulse of the two seventy-year-old colleagues of the victim! For six weeks he remained unconscious and for almost three months did not even recognize his loved ones. For health reasons, Landau could not go to Stockholm to receive the 1962 Nobel Prize, which he was awarded "for his fundamental theories of condensed matter, especially liquid helium." The prize was presented to him in Moscow by the Swedish Ambassador to the Soviet Union. Landau lived for another six years, but there were too many severe injuries and injuries. Severe pains tormented Landau for a long time and almost constantly. And he could not return to science. Landau said before his death: "I lived my life well. I always succeeded in everything." Lev Davidovich died on April 1, 1968. In addition to the Nobel and Lenin Prizes, Landau was awarded three State Prizes of the USSR. He was awarded the title of Hero of Socialist Labor. In 1946 he was elected to the USSR Academy of Sciences. The academies of sciences of Denmark, the Netherlands and the USA, the American Academy of Sciences and Arts, and the French Physical Society have elected him as their member. Physical Society of London and Royal Society of London. He was awarded the Max Planck medal, the Fritz London Prize. Author: Samin D.K.
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