However, Yang Zhenning was hacked by many people in China. Those who have hacked him have been pursuing vague moral issues, but they have not really understood his great personal achievements in physics.
I talked to the teacher in Tsinghua. Yang Zhenning and Weng Fan have a very good relationship. If they really love each other, what do you have to spray? Others say that Yang Zhenning retired to China to earn money for the elderly, which is useless. But in fact, Yang Zhenning's return to Tsinghua can give full play to his influence and mobilize a lot of academic resources, which is very beneficial to the development of related disciplines in Tsinghua. Otherwise, people really think he is not worth the price?
In the Internet age, I hope everyone can have their own judgment and not be led by some media. In particular, the evaluation of such a complex individual needs to be more cautious.
Qingbei is often hacked, and many people don't understand the internal situation. They are always hacked for the sake of hacking, which makes us students feel sad.
People often compare Hawking with contemporary physicists, such as Yang Zhenning, Fermi and Pauli. To tell the truth, Hawking is not as successful as their achievements. As for saying "Hawking is the greatest scientist after Einstein", this is just the rhetoric of media propaganda, which is not objective in academic circles. It can only be said that Hawking is a great scientist, but in terms of academic achievements alone, compared with Einstein and C.N. Yang, it is not at all a level. Take Yang Zhenning as an example. Yang is indeed the greatest physicist alive today, and there is no one. His achievements are numerous and far-reaching. His achievements have become the basic theories of many related branches in physics and even mathematics, such as Young-Mills gauge field theory and Young-Baxter equation. These are more important and fundamental than Hawking's most representative achievements: singularity theorem and Hawking radiation from black holes. If we look at the citation rate of Hawking's papers, we will find that the citation rate of his papers is not as high as that of Witten, a famous string theorist. But then again, we may have to ask, why are there physicists who are much better than Hawking at the same time, and why is Hawking so famous? To a large extent, it is because of his physical disability, determined image and admirable quality. As a person who is deeply troubled by the "frozen man", Hawking has made great achievements in science, and his seriousness and persistence are really admirable.
We can have a brief look at Hawking's work. Hawking's work mainly focuses on general relativity and cosmology. He and Penrose jointly published a series of papers and founded the mathematical structure theory of modern cosmology:
Singularity Theorem: Both Hawking and Penrose proposed and proved the singularity theorem, which was a very important work of Hawking in his early years. The singularity theorem tells us that "as long as the general theory of relativity is correct, the causality is good, the energy is positive definite, and there is at least a little matter in space-time, then there is a singularity in this space-time, or at least there is a physical process, and time has a beginning and an end, or both." This theorem profoundly shows that the singularity of the Big Bang is the inevitable result of Einstein's general theory of relativity. Although this achievement is important, it is still a small point and a solution to a small problem under the framework of general relativity.
Black hole mechanics (black hole thermodynamics): Hawking first demonstrated that the event horizon of a black hole must have a spherical topological structure. Later, Hawking and his collaborator Bardeen established the connection between black holes and the basic laws of thermodynamics in 1973. For example, the surface area a and surface gravity \ κ of the black hole horizon can be compared with thermodynamic quantities such as entropy s and temperature t, respectively. During this period, it can be said that Hawking's research in the field of classical general relativity was the best in the world at that time.
Hawking radiation: Hawking's most important job is to prove the thermal radiation of black holes, which is now called Hawking radiation. The existence of black hole thermal radiation is strictly proved from differential geometry for the first time, which is a strict blackbody spectrum. This work is the core of black hole theory, and night is extremely important in theory. The current problem is that it has not been verified by experiments, and it is difficult to be verified by experiments, because Hawking radiation is very small, and any existing technology can't directly observe it.
Virtual Time and Infinite Imagination of the Universe (Hawking's Infinite Universe Model): A set of quantum methods developed by Hawking and hartle to deal with the singularity of the Big Bang, that is, the "borderless" method, that is, the singularity is replaced by a smooth "hat". In order to understand this view, Hawking introduced the concept of virtual time (or Euclid) and transformed Einstein's pseudo-Riemannian geometry into standard Riemannian geometry. Although the work is original, there are still many difficulties. This is Hawking's work in his later years, but it has never attracted people's attention. Hawking admits that everyone generally accepts the thermal radiation theory of black holes, but he thinks that the hypothesis that the universe is boundless is more important. However, it must be said that Hawking's method is not the most popular, although it is highly respected. However, through the borderless hypothesis, we can answer a question that the public is very interested in: "What was the universe like before the Big Bang?" . According to the borderless hypothesis, the big bang singularity is equivalent to the south pole of the earth, because there is no place farther south than the south pole, so there is nothing before the big bang singularity. )
Compared with Yang Zhenning, Yang's achievements are not only much more in quantity, but also more important and basic. The following are the most representative achievements of Yang 13:
Parity is not conserved in weak interaction: this is the early discovery of parity in weak interaction by Yang and Li Zhengdao (). Previously, physicists thought parity was conserved in strong interaction, weak interaction and electromagnetic interaction. Later, the team led by Wu Jianxiong (Wu Jianxiong) proved through experiments that parity is indeed not conserved in weak interaction, which caused an uproar in physics. Because of this extremely important work, Yang and Li shared the 1957 Nobel Prize in Physics. Anyone who studies physics should know the importance of symmetry in physics, so parity conservation has an intuitive attraction, so it is not difficult to understand how important this subversive work is.
Three kinds of discrete symmetries: time reversal, charge binding and parity: Yang, Li Zhengdao and Ou Mai published papers to discuss the relationship between time non-conservation, charge and parity. This paper has a decisive influence on all theoretical analysis of CP non-conservation in 1964. Theoretical discussion of high-energy neutrino experiment: 1960, experimental physicist Schwartz pointed out how to obtain more experimental information of weak interaction through neutrino beam. Li Zhengdao and Yang discussed the importance of high-energy neutrino experiment in theory. This is the first theoretical analysis of neutrino experiment, which leads to many important research work later.
Phenomenological framework of CP non-conservation: 1964, Christenson, Cronin, Fitch and Turlay found that CP was non-conservation. Yang and his student Wu Dajun made a phenomenological analysis of CP non-conservation, and established a phenomenological framework for the later analysis of this phenomenon. This paper defines the theoretical framework and terminology still used in this field.
Young-Mills gauge field theory: This is the basis of modern gauge field theory, an important physical breakthrough in the second half of the 20th century, and also the basis of weak current unified theory, which provides a powerful tool for studying the structure of hadrons and other basic particles. 1954, Yang-Mills gauge field theory (that is, non-Abelian gauge field theory) was published. In two short essays, Yang and his student Mills extended Weil's Abelian gauge theory to non-Abelian gauge theory. It can be said that Yang-Mills theory has the lofty status of "creating the world", and its success is a revolution in the history of physics.
The integral form of gauge field theory: Yang-Mills theory also pushes the relationship between physics and mathematics to a new height. Around 1970, Yang devoted himself to studying the integral form of gauge field theory and discovered the importance of non-integrable phase factor, thus realizing that gauge field has profound geometric significance.
Correspondence between gauge field theory and fiber bundle theory: As early as1970s, Yang realized that the geometric meaning of gauge field and the integral form of gauge theory were actually a geometric development, so he learned fiber bundle theory from J. Simons. Yang finally realized that the physicist's so-called specification corresponds to the mathematician's so-called principal coordinate bundle, while the physicist's so-called potential corresponds to the mathematician's so-called principal fiber bundle. In 1975, he published a paper, which revealed that the gauge field geometrically corresponds to the connection on the fiber bundle.
Phase transition theory: 1952 Yang published three important papers on phase transition. The first paper is his independent paper on spontaneous magnetization of two-dimensional Ising model, and the critical exponent of 1/8 is obtained. This is the longest calculation Yang has ever done, an absolute feat. Dyson called it "a master exercise of Jacobian elliptic function theory". 1952, Yang also cooperated with Li Zhengdao to complete and publish two papers on phase transition theory, which extended the study of Ising model to lattice gas model and strictly calculated Maxwell diagram of gas-liquid phase transition. Two articles were submitted and published at the same time, which aroused Einstein's interest. The climax of Yang and Li's two papers is the unit circle theorem in the second paper (now called Li-Yang's unit circle theorem), which points out that the zero point of the giant partition function of the lattice gas model attracting interaction lies on the unit circle on the complex plane. In statistical mechanics and field theory, this theory is still attractive.
Boson many-body problem: Yang and his collaborators published or completed a series of papers about thin hard ball boson many-body system around 1957, which is a well-defined mathematical model. Previously, Yang and Luttinger jointly published two papers, applying Fermi pseudopotential method to this field. Later, Yang and Li Zhengdao first obtained the correct ground state energy correction by double collision method, and then obtained the same results as Huang and Li Zhengdao by pseudo potential method. They got the first two energy corrections or the gradual expansion of sound speed, the most surprising of which is the famous square root correction (later called Li-Huang-Yang correction), but it could not be verified by experiments at that time. Unexpectedly, 50 years later, with the development of cold atomic physics, this correction term was confirmed by experiments.
Yang-Baxter equation: 1967 Yang found that the fermion quantum many-body problem in the repulsive potential of one-dimensional Δ function can be transformed into a matrix equation, which was later called Yang-Baxter equation. Yang's work has opened the door to two fields. Later, it was found that Young-Baxter equation is an extremely important equation in mathematics and physics, which is closely related to kink theory, Hopf algebra and string theory.
Exact solution of the boson in the repulsive potential of one-dimensional \delta function at finite temperature: 1969 Yang pushed the boson problem in the repulsive potential of one-dimensional \delta function to finite temperature. This is the first time in history to get the exact solution of the quantum statistical model of interaction at finite temperature. Recently, this model and its results have also been experimentally realized and verified in cold atomic systems.
Theoretical Explanation of Superconductor Flux Quantization: 196 1 When Yang visited Stanford University in, Fei Zhengqing and Deaver of the university found that the flux in the superconducting ring was quantized in hc/2e units. Yang and byers gave a correct theoretical explanation for this phenomenon.
Off-diagonal long program: In 1962, Yang put forward the concept of off-diagonal long program, described the essence of superfluidity and superconductivity in a unified way, and also deeply discussed the root of magnetic ionization. This is a key concept of contemporary condensed matter physics. From 1989 to 1990, Yang discovered the eigenstate with off-diagonal long program in Hubbard model closely related to HTS, and found its SO(4) symmetry with.
In fact, the last thing I want to say is that it is meaningless to compare two physicists. We can objectively explain what their achievements are, but physicists like Hawking and Yang are not in a research field after all. We can say who is greater than who, but this comparison is actually worthless. Anyway, I think scientists such as Hawking and Yang have left a brilliant stroke on the road of human understanding of the world and the universe, and they all deserve our admiration and respect. Now that Hawking has passed away, it is very sad. He used to be a man who looked up at the vast universe, but now he has become a stellar universe.