In a short time, quantum mechanics has developed rapidly. Heisenberg gave a matrix mechanical equation describing the movement of microscopic particles. When Schrodinger, an Austrian physicist, gave the equation of wave mechanics almost at the same time, which caused the debate on the nature of micro-particle physics, Pauli, who was studying at the Institute of Theoretical Physics with Heisenberg, discovered the equivalence between matrix mechanics and wave mechanics. Subsequently, Dirac, a young British physicist, developed a more general theory of quantum mechanics-transformation theory in Copenhagen. Heisenberg then put forward the uncertainty principle, and Bohr put forward the complementary principle (union principle) with more philosophical significance. Heisenberg, Pauli and Dirac all won the Nobel Prize in Physics. Other important figures of Copenhagen School include Weizak, Clem, Jordan and Gamov. Members in Copenhagen are all focused on the explanation of the basis of quantum mechanics. They seek common ground while reserving differences on the main basic viewpoints, improve in discussion and improve in argumentation, and together form the main ideas and viewpoints of the Copenhagen School, which is called the orthodox or classic "Copenhagen Interpretation". They believe that observable measurement is the foundation and basis of establishing theory, and human subjective components can not be ruled out logically, so quantum theory is the combination of subjective and objective factors; Quantum transition is the most basic concept of quantum physics, and the movement of microscopic particles is discontinuous, which makes it impossible to measure two interrelated variables according to the uncertainty principle and accurately measure them at the same time. The wave function describing microscopic particles is a kind of probability wave (mainly explained by German scientist Born), and the causal law and determinism established in the macro field are not established in the micro field; The microscopic phenomena observed in the experiment can only be described by the usual classical language, and the wave-particle duality paradox of microscopic particles is the result of the classical language description, so the microscopic phenomena described by the classical language are complementary and mutually exclusive.
Different people have different descriptions of Copenhagen spirit, such as "the virtue of completely free judgment and discussion"; "A mixture of high pursuit of knowledge, bold spirit of adventure, profound research content and happy optimism"; "Bohr's inspiration and guidance are consistent with the genius and personal talent of young physicists around him, and they are the complement of leaders and the masses"; Because of his insight and inspiring power, Bohr lit the torch of imagination and let the intelligence of people around him give full play. Bohr, Danish physicist, founder of Copenhagen School. 1885 1903/kloc-0 was born in Copenhagen on October 7th, and entered the Department of Mathematics and Natural Sciences of the University of Copenhagen, majoring in physics. 1907 won the gold medal from the Royal Danish Academy of Science and Literature for his paper on the surface tension of water, and 1909 and11obtained the master of science and doctor of philosophy degrees from the University of Copenhagen in. Then I went to England to study, first in the Cavendish laboratory hosted by join Thomson in Cambridge, and then a few months later I moved to Manchester and joined a scientific group headed by E Rutherford. Since then, I have established a long-term close relationship with Rutherford. At that time, Rutherford's nuclear atom model had just been established, and people still knew little about the internal structure and motion of atoms. However, both the few laws in spectroscopy and the periodic table of elements in chemistry remain at the level of empirical laws and have not been satisfactorily explained theoretically. On the other hand, Rutherford's nuclear atom model is obviously incompatible with classical physics, that is, according to classical theory, Rutherford's model will not have the stability of material atoms. In this situation, Bohr initially established his own atomic structure theory after a month or two of sleepless nights. He returned to China in the summer of 19 12 and worked as a lecturer at his alma mater. He continued to study and expand his theory in his spare time. 19 13 years, he published a long paper in three parts on the topic of "On Atomic Structure and Molecular Structure", paving the way for atomic physics in the 20th century. In his own theory, he adopted the existing quantum concepts at that time, put forward several basic postulates, and put forward concepts such as atomic steady state and quantum transition, which are still very important today. It strongly impacted the classical theory and promoted the formation of quantum mechanics.
Bohr's theory has achieved quite satisfactory results in explaining the spectrum of hydrogen atoms, and corrected the popular view in explaining the origin of some lines in the star spectrum. His steady-state concept has been verified more and more accurately by experiments, and some of his theoretical predictions have also been confirmed by experiments, with remarkable achievements. However, this theory can't explain the spectra of other elements well at first, and it can't explain the intensity and polarization of any spectral line at all. However, Bohr's grand goal is to explain the physical and chemical properties of atoms and molecules from the beginning, especially the periodic table showing the changes of these properties. In order to achieve this goal and further explore the relationship between classical theory and quantum theory, Bohr gradually developed in 65438+. He believes that there is a certain correspondence between the motion of periodic system described by classical theory and the actual quantum motion of the system; Specifically, there is a simple correspondence between the classical generalized coordinate Fourier coefficient of the system and the transition probability of the system. Later, this theory was called correspondence principle. This principle became a bridge from classical theory to quantum theory at that time, and later formed a direct prelude to Heisenberg matrix mechanics. Bohr's theory has caused a lot of research work. Bohr absorbed other people's research results, and made use of his own correspondence principle to put forward relatively reasonable theoretical explanations for the spectra of various elements and X-ray spectra, the (normal) Zeeman effect and Stark effect of spectral lines, the grouping of electrons in the periodic table of atoms and elements, and even the formation of molecules. Because of these brilliant achievements, he won the 1922 Nobel Prize in physics.
192 1 year, the Institute of Theoretical Physics of the University of Copenhagen was established at Bohr's initiative. Bohr led the institute for 40 years. This institute has trained a large number of outstanding physicists, and once became the most important and active academic center in the world during the rise of quantum mechanics, and it still has a high international status.
When the mathematical expression of quantum mechanics in the period of 1924- 1926 was basically established, M Born quickly put forward the probability explanation (statistical explanation) of wave function, and W·K· Heisenberg also put forward and expounded his uncertainty principle according to his own understanding. These two interrelated viewpoints constitute the important content of the so-called Copenhagen viewpoint, and Bohr, as the "spiritual leader" of the Copenhagen school, put forward his "complementary" viewpoint (hereinafter referred to as "complementary principle") and gradually developed his "complementary philosophy".
The proposition of Heisenberg principle has caused a series of philosophical disputes: Is the statistics of the basic laws of micro-motion of matter essential? Must determinism or causality be abandoned or popularized? Can quantum mechanics be considered a "complete" theory? What is the relationship between microscopic objects and measuring instruments? Is there a final limit to people's understanding of things? And so on.
Bohr's first supplementary viewpoint in 1927 is to try to answer these many questions. There is no fixed written expression of this view, and Bohr put forward different views on different occasions. According to him, objects in the material world, concepts in the spiritual world and words in the language all have many different "aspects", just as the same multivalued function in mathematics has many different values. For the same research object, once people admit some aspects of it, they must give up others. In this sense, the two are mutually exclusive. However, those other aspects cannot be completely abolished, because people must use them under other appropriate conditions (at this time, they must give up those aspects that should be recognized under the above conditions). In this sense, the two are "complementary". For example, Bohr thinks that the "particles" and "fluctuations" of microscopic objects are mutually exclusive and complementary. This idea is the basic content of the so-called complementary principle.
According to Bohr, it is meaningless to investigate which of the two mutually exclusive and complementary aspects is more "fundamental"; People can only and will get a complete description of things, and all aspects and related conditions must be taken into account.
Bohr thinks that his complementary principle is an infinitely broad philosophical principle. In his view, in order to accommodate and compare "our experience", the concept of causality is not enough, and it must be replaced by a complementary concept, a "broader thinking framework". Therefore, he said, complementarity is a "reasonable promotion" of causality. Especially in his later years, he discussed countless problems in physical science, biological science, social science and philosophy with this view, which had a very important influence on western academic circles.
Bohr's complementary philosophy is supported by many influential scholars, but it is also opposed by other equally influential scholars. Around these issues, there has been an academic debate with few precedents in history. This debate has been going on for decades, and it is still inconclusive. It seems that it is far from over.
As a student of Rutherford, Bohr not only studied atomic physics and philosophy related to quantum mechanics, but also paid close attention to nuclear issues. Since 1930s, his institute has devoted more efforts to nuclear physics. In the mid-1930s, he put forward a droplet model of the nucleus, thinking that the particles in the nucleus are a bit like molecules in droplets, their energy obeys some statistical distribution law, and the movement of particles near the "surface" leads to the appearance of "surface tension", and so on. This model can explain some experimental facts and is the first relatively correct nuclear model in history. On this basis, he put forward the concept of compound nucleus in 1936, thinking that low-energy neutrons will interact with many nuclei after entering the nucleus, leading to the disintegration of the nucleus. This rather simple picture of the nuclear reaction mechanism is still useful today.
When L. Maitenaz and O. R.frisch put forward heavy nuclear fission's idea according to O. Hahn's experiment, Bohr and others immediately understood this idea and made a more detailed field study on the fission process. Bohr also predicted that uranium -235, not uranium -238, was the cause of slow neutron fission. The paper published by him and J.A. Wheeler in Physical Review 1939 is considered as an important achievement of nuclear physics in this period. As we all know, this research has led to the massive release of nuclear energy.
Bohr loved peace, advocated democracy and opposed aggression and dictatorship all his life. 1933 After Hitler came to power in Germany, Bohr went to Germany to arrange the escape of persecuted intellectuals, and later organized a special organization in Denmark to assist and rescue these people. At that time, a large number of famous scholars in Germany and Italy were helped by Bohr and others, which played an important role in the history of academic and cultural development. After Nazi Germany took control of Denmark, Bohr initially stayed at home and kept close contact with anti-enemy organizations. It was not until 1943 that Wolfenstein Castle ordered his arrest that he risked his life and went to England via Sweden and soon arrived in the United States. During his stay in the United States, he participated in the development of the atomic bomb and made important contributions, but his motivation was entirely to fight back against the Nazis. He realized the danger of the nuclear arms race from the beginning. During this period, he repeatedly contacted the leaders of Britain and the United States and suggested that they make arrangements to control and limit nuclear weapons as soon as possible, but without success. 1945 after world war ii, he resolutely broke off relations with the manufacture of any nuclear weapons. Since then, he has strongly called for peace and published an open letter to the United Nations in 1950. At the same time, he vigorously promoted the peaceful use of nuclear energy, advocated academic international cooperation, and initiated and led the European Nuclear Center and the Nordic Institute of Atomic Physics.
Since 19 13 became famous, Bohr has been awarded many lofty honors and titles by governments and academic groups all over the world. He was re-elected as chairman of the Royal Danish Academy of Sciences for many times and visited many countries in the world. /kloc-in the summer of 0/937, he came to China and visited Shanghai, Hangzhou, Nanjing and Beiping. He was very friendly to the people of China. 1947, the Danish government decided to award him a senior medal, requiring the decorated person to have a national emblem. Bohr personally designed his national emblem, and its central pattern adopted the ancient "Taiji Diagram" of China, which vividly expressed his complementary thoughts.
Bohr died in Copenhagen on1962116 10.