In physics, Landau's contribution is various. In the name of Moses Ten Commandments, people summarized Landau's contribution to physics as "Landau Ten Commandments". The results of this 10 are: density matrix and statistical physics in quantum mechanics (1927); Theory of free electron diamagnetism (1930); Study on second-order phase transition (1936 ~1937); Magnetic domain theory of ferromagnetism and theoretical explanation of antiferromagnetism (1935); Mixed state theory of superconductors (1934); Nuclear probability theory (1937); Quantum theory of superfluidity of helium 4 (1940 ~1941): Charge confinement theory of elementary particles (1954); Quantum theory of Fermi liquid (1956); CP invariance of weak interaction (1957).

Feynman's scientific work also involves many fields. Among them, the most important is the path integral theory of quantum mechanics and his full quantum electrodynamics (QED) written in the form of path integral, which makes it in the form of relativistic covariation, avoids the difficulty of divergence through renormalization, and solves the self-energy problem of electrons. Using this theory, we can calculate the Lamb shift and abnormal magnetic moment of electrons quite accurately, which can't be handled by the old theory. In this process, he also developed Feynman diagram technology, which is very important in field theory. Today, path integral and Feynman diagram have become the common language of theoretical physicists, just as calculus is important to Newtonian mechanics.

Landau and Feynman both use women and sex to express their love for physics. Feynman said that studying physics is like sex for him. Although there are few utilitarian uses, they are absolutely indispensable. Landau once said sourly, "All the beautiful girls have married others, and now we can only pursue some less beautiful girls." The pretty girl here refers to quantum mechanics, which is the basis of modern physics. It was founded by three physicists Heisenberg, Schrodinger and Dirac in 1930s. Landau was several years younger than them, so he failed to catch up with the most critical gold rush in the history of physics.

Judging from the scientific work of Landau and Feynman, it is difficult for us to distinguish who is more "powerful". Landau's work mostly focuses on condensed matter physics, and he is considered as the founder of condensed matter physics, the largest branch of modern physics [2]. However, Landau has been worried that he was "born out of time" and failed to catch up with the creation of quantum mechanics. Feynman's work mainly focuses on quantum field theory, and his path integral theory of quantum mechanics is considered as the third equivalent theoretical form of quantum mechanics [3]. This job is enough to make Landau envy. It can be said that part of Landau's desire to associate his name with the founder of quantum mechanics was realized by Feynman.

Landau and Feynman are both excellent educators. If we walk into any university library, we will find that physics textbooks and lectures written by Landau or Feynman are the most popular. Among them, Landau's Course of Theoretical Physics and Feynman's Lecture Notes on Physics are the most talked about. In addition, Landau also has a set of Popular Physics specially written for high school students and college readers. Feynman also has graduate-level textbooks such as lectures on statistical mechanics and quantum electrodynamics. It seems that both of them have a hobby of describing "all" physics in their own style. But interestingly, Landau and Feynman almost never "wrote" these books. They are more like missionaries talking about their physics in a forum or research group. Just as the Bible is a classic compiled by the disciples of God according to their words and deeds, the authors of Landau are mainly their students and collaborators. Feynman's book was compiled by later generations based on lecture recordings and student notes. Feynman usually speaks with a piece of paper in class.

Landau, as a symbol of theoretical physics in the former Soviet Union, is the leader of the famous Landau school. In this research group, students must complete Landau's theoretical physics course before they can enter the research. It is said that Landau himself has never read literature, and his students will discuss the literature he has read with him. Moreover, Landau School has produced many masters, such as Abri Kosov, winner of the 2003 Nobel Prize, and Li Fuzi. In contrast, Feynman, as a mentor, did not cultivate a particularly successful disciple in physics. But Feynman is very enthusiastic about the spread of physics among the public. He often gives lectures to undergraduates all over the world and gives scientific lectures to the public.

Feynman, who is smart and lively, lives in the United States where the media is developed, and obviously attracts more public attention outside physics. In the public eyes, Feynman is a legendary prodigal son living in the physical world. Landau's fame is mainly confined to academic circles, and he is somewhat overbearing and outspoken in academic circles. He once said: "Theoretical physics is a complex science, and no one can understand it." You are welcome to respond to the words of the older generation of physicists about Fei, and shoot some scientific papers that proved to be extremely important later without mercy.

1938, Landau was imprisoned on suspicion of being a German spy. After a year in prison, he was rescued by physicists at home and abroad including Bohr, but those days must be unforgettable for him. He wrote:

I spent a year in prison, and obviously I can't live for another six months. I've been in prison for a year, and I'm obviously going to die in half a year. )

1962, Landau suffered another serious car accident. In the car accident, Landau broke 1 1' s heel and skull fracture. After several clinical death judgments, the doctor rescued Landau from death, but he lost the ability to do physical research. Six years later, 60-year-old Landau left us prematurely. Landau can be said to be a tragic figure. Although he has achieved unprecedented success in science, he has left too many regrets for future generations, making them feel sorry for him.

Feynman is obviously a comic figure, and his talent has been fully developed and displayed in all aspects. Feynman played drums, studied ancient Egyptian hieroglyphics, and went to the dance to play with female college students, just like a talented urchin. Feynman's favorite is of course theoretical physics. Before he died, the blackboard in his office was painted with Bethe Ansatz's super question. But Feynman's show-off is not for everyone. Gherman, the father of quarks, made no secret of his hostility to Feynman. Usually, if Feynman says something, gherman will attack Feynman sarcastically and Feynman will fight back immediately. Feynman usually laughs off this fierce confrontation, which is almost "cruel", but afterwards gherman becomes more and more angry and irritable. Gherman wanted to avoid getting angry, and then he tried to avoid Feynman. If gherman saw Feynman giving a lecture, he would start reading notes in a monotonous tone. Only when Feynman leaves will he speak vividly again.

Surprisingly, Feynman is as Jewish as Landau, and both of them are Jews from the former Soviet Union. Feynman was born in new york, but his father Melville is from Minsk. Feynman's father loved physics and was the enlightenment of Feynman Jr., Landau's father was an engineer, and the academic and mathematical traditions of the Russian nation and Jews were undoubtedly the real fathers who gave birth to two physical geniuses. Landau and Feynman's influence on physics will never be a thing of the past.