Lev Landau (years of life - 1908-1968) - the great Soviet physicist, a native of Baku. He owns many interesting studies and discoveries. Can you answer the question, Leo Landau, for which he received the Nobel Prize? In this article we will talk about his achievements and the main facts of his biography.
Origin of Leo Landau
You can talk for a long time about such a scientist as Lev Landau. Years of life, occupation and achievements of this physicist - all this probably interests readers. Let's start from the very beginning - with the origin of the future scientist.
He was born in the family of Love and David Landau. His father was a rather famous oil engineer. He worked in the oil fields. As for the mother, she was a doctor by profession. It is known that this woman carried out physiological studies. As you can see, Leo Landau was a native of an intelligent family. His older sister, by the way, became a chemical engineer.
years of education
Lev Davidovich studied in high school, which he brilliantly graduated at the age of 13 years. His parents felt that their son was still very young to study at a higher educational institution. Therefore, they decided to send him to the Baku Economic College for one year. Then, in 1922, he was admitted to Baku University. Here Lev Landau studied chemistry and physics. Two years later, Lev Davidovich transferred to Leningrad University, to the Faculty of Physics.
The first scientific works, graduate school
At the age of nineteen, Landau became the author of four scientific papers that were published. In one of these works, the so-called density matrix was first used. This term is now widely used. He describes quantum energy states. Landau graduated from the university in 1927. Then he entered graduate school, choosing the Leningrad Institute of Physics and Technology. In this educational institution, he worked on quantum electrodynamics and magnetic theory of the electron.
Business trip
In the period from 1929 to 1931, Lev Landau was on a business trip. Years of life, occupation and achievements of this scientist are associated with close cooperation with foreign colleagues. So, during a business trip, he traveled to Switzerland, Germany, the Netherlands, England and Denmark. During these years he met and met the founders of quantum mechanics, which then just appeared. Among the scientists Landau met were Wolfgang Pauli, Werner Heisenberg, and Niels Bohr. To the latter, Lev Davidovich retained friendly feelings for his whole life. This scientist especially strongly influenced Landau.
Lev Davidovich, while abroad, carried out important studies of free electrons (their magnetic properties). In addition, together with Peierls, he conducted research on relativistic quantum mechanics. Thanks to these works, Lev Landau, whose occupation interested foreign colleagues, became one of the leading theoretical physicists. The scientist learned how to handle very complex theoretical systems. It should be noted that subsequently this skill was very useful to him when Landau began to conduct research relating to low-temperature physics.
Moving to Kharkov
Lev Davidovich in 1931 returned to Leningrad. However, he soon decided to move to Kharkov, which at that time was the capital of Ukraine. Here, the scientist worked at the Ukrainian Institute of Physics and Technology, was the head of its theoretical department. At the same time, Lev Davidovich was the head of the departments of theoretical physics at Kharkov University and the Kharkov Mechanical Engineering Institute. In 1934, the USSR Academy of Sciences awarded him a doctorate in physical and mathematical sciences. For this, Landau did not even need to defend a dissertation. The title of professor was awarded as early as next year to such a scientist as Lev Landau.
His occupation covered more and more new fields of science. Landau in Kharkov published works on topics such as sound dispersion, the origin of stellar energy, light scattering, energy transfer during collisions, superconductivity, magnetic properties of various materials, etc. Thanks to this, he became known as a theoretician with unusually versatile scientific interests.
A distinctive feature of Landau's works
Subsequently, when plasma physics appeared, Landau's work on particles interacting electrically proved to be very useful. Having borrowed some concepts from thermodynamics, the scientist expressed a number of innovative ideas regarding low-temperature systems. It must be said that all Landau's works are characterized by one important feature - the virtuoso use of the mathematical apparatus in the search for solutions to complex problems. Leo Landau made a significant contribution to quantum theory, as well as to studies of the interaction and nature of elementary particles.
Leo Landau School
The scope of his research is truly wide. They cover almost all the main areas of theoretical physics. Due to such a breadth of his interests, the scientist attracted many talented young scientists and gifted students to Kharkov. Among them was Lifshits Evgeny Mikhailovich, who became an employee of Lev Davidovich and his closest friend. The school, which grew up around Lev Landau, turned Kharkov into one of the leading centers of theoretical physics in the USSR.
The scientist was convinced that a theoretical physicist should be thoroughly savvy in all areas of this science. To this end, Lev Davidovich developed a very strict training program. He called this program a "theoretical minimum." Applicants who wanted to participate in a seminar led by him had to meet very high requirements. Suffice it to say that for 30 years, despite many comers, only 40 people have passed the "theoretical minimum" exams. However, those who succeeded, Lev Davidovich generously devoted his attention and time. In addition, they were given complete freedom of choice when choosing a research topic.
Creating a course in theoretical physics
Landau Lev Davidovich maintained friendly relations with his employees and students. They lovingly called the scientist Dow. To help them in 1935, Lev Davidovich created a detailed course in theoretical physics. It was published by Landau together with E. M. Lifshitz and was a series of textbooks. The authors updated and revised their content over the next 20 years. These benefits have gained immense popularity. They have been translated into many languages of the world. Currently, these textbooks are rightly considered classic. In 1962, Landau and Lifshitz received the Lenin Prize for creating this course.
Work with Kapitsa
Lev Davidovich in 1937 responded to the invitation of Peter Kapitsa (his photo is presented below) and became the head of the Department of Theoretical Physics at the Moscow Institute of Physical Problems, newly created at that time. However, the next year the scientist was arrested. The false accusation was that he was engaged in espionage in favor of Germany. It was only thanks to the intervention of Kapitsa, who personally turned to the Kremlin, that Lev Landau was released.
When Landau moved from Kharkov to Moscow, Kapitsa was just doing experiments with liquid helium. If the temperature drops below 4.2 K (absolute temperature is measured in degrees Kelvin and counts from -273.18 ° C, that is, from absolute zero), gaseous helium becomes a liquid. In this state, it is called helium-1. If you lower the temperature to 2.17 K, it goes into a liquid called helium-2. It has very interesting properties. Helium-2 can easily flow through the smallest holes. It seems as if his viscosity is completely absent. The substance rises up the vessel wall, as if gravity does not affect it. In addition, its thermal conductivity exceeds the thermal conductivity of copper hundreds of times. Kapitsa decided to call helium-2 a superfluid. However, when checking it turned out that its viscosity is not zero.
Scientists have suggested that such unusual behavior is explained by effects that are not related to the field of classical physics, but to quantum theory. These effects appear only at low temperatures. Usually they make themselves felt in solids, since under these conditions most substances freeze. The exception is helium. This substance remains liquid to absolute zero if it is not subject to high pressure. Laszlo Tissa in 1938 suggested that in reality liquid helium is a mixture of two forms: helium-2 (superfluid liquid) and helium-1 (normal liquid). When the temperature drops to almost absolute zero, the first becomes the dominant component. This hypothesis explains the appearance of different viscosities under different conditions.
As Landau explained the phenomenon of superfluidity
Leo Landau, whose brief biography describes only his main achievements, was able to explain the phenomenon of superfluidity, using a completely new mathematical apparatus. Other scientists relied on quantum mechanics, which was used to analyze the behavior of individual atoms. Landau, on the other hand, examined the quantum states of a liquid in almost the same way as if it were a solid. He hypothesized that there are two components of arousal, or movement. The first of these is phonons, which describe the normal rectilinear propagation of sound waves at low values of energy and momentum. The second is rotons, which describe the rotational motion. The latter is a more complex manifestation of excitations arising at higher values of energy and momentum. The scientist noted that the observed phenomena can be explained by the contributions of rotons and phonons and their interaction.
Landau argued that liquid helium can be considered as a "normal" component, which is immersed in a superfluid "background". How can we explain the fact that liquid helium flows out through a narrow gap? The scientist noted that only the superfluid component in this case flows. And rotons and phonons collide with the walls holding them.
The meaning of the Landau theory
Landau's theory, as well as its further improvements, played a very important role in science. They not only explained the observed phenomena, but also predicted some others. One example is the propagation of two waves with different properties and called the first and second sound. The first sound is ordinary sound waves, while the second is a temperature wave. Thanks to the theory created by Landau, scientists were able to make significant progress in understanding the nature of superconductivity.
The years of World War II and the post-war period
Lev Davidovich during the Second World War was engaged in the study of explosions and combustion. In particular, he was interested in shock waves. After May 1945 and until 1962, the scientist worked on various tasks. In particular, he investigated a rare helium isotope having an atomic mass of 3 (usually its mass is 4). Lev Davidovich predicted the existence of a new type of wave propagation for this isotope. "Zero sound" - as Lev Davidovich Landau called it. His biography is marked, in addition, by participation in the creation of the atomic bomb in the USSR.
Car accident, Nobel Prize and the last years of life
At the age of 53, he had a car accident, as a result of which he received severe injuries. Many doctors from the USSR, France, Canada, Czechoslovakia fought for the life of a scientist. He stayed unconscious for 6 weeks. For three months after the car accident, even Lev Landau's relatives did not recognize him. The Nobel Prize was awarded to him in 1962. However, for health reasons, he could not go to Stockholm in order to get it. In the photo below, you can see L. Landau with his wife in the hospital.
The prize was awarded to a scientist in Moscow. After this, Lev Davidovich lived another 6 years, but he could not return to research. Lev Landau died in Moscow as a result of complications from his injuries.
Landau family
In 1937, the scientist married Drobantseva Concordia, a process engineer in the food industry. This woman was from Kharkov. The years of her life - 1908-1984. A son was born in the family, who later became an experimental physicist and worked at the Institute of Physical Problems. The photo below shows L. Landau with his son.
This is all that can be told about such a scientist as Lev Landau. His biography, of course, includes only the basic facts. The theories that he created are complex enough for an unprepared reader. Therefore, the article only briefly describes what made Lev Landau famous. The biography and achievements of this scientist are still of great interest around the world.