Chinese scholar Yin Xi has once again become the focus of attention because he gave up his Chinese citizenship and immigrated to the United States. The last time he became a news figure was in September 2015 when he was appointed as the "youngest Chinese full professor at Harvard University". In fact, Yin Xi was naturalized in the United States. It was also in 2021, and somehow it suddenly became popular again.
Yin Xi has been called a "child prodigy"
For a long time, Yin Xi has been called a "child prodigy", but he is indeed worthy of this title: he was admitted to the Youth Class of the University of Science and Technology of China at the age of 12, and earned US$20,000 at the age of 18. He received a full scholarship to study for a doctoral degree at Harvard University. He received his doctorate at the age of 23. He was appointed as an assistant professor at Harvard University at the age of 25 and was promoted to a full professor in the Department of Physics at the age of 32. In total, he has lived in the United States for 21 years, married and had children there.
The main reason why Yin Xi has stayed in the United States is not only the high salary he can get at Harvard, but also the fact that the field of his research is very "extraordinary". Some people say that "cannot find 100 people" in China to engage in this research. This is string theory .
String theory often uses one-dimensional strings to twist into a two-dimensional membrane structure to explain microscopic particles
Perhaps 99.9% of friends do not understand string theory. It is too profound and even a bit mysterious. But as long as you are a science fiction fan, there is almost no one who does not know " multi-dimensional space " or " high-dimensional space ". This multi-dimensional space is the description of the universe by string theory.
Traditional physics believes that all objects have three dimensions: "length, width, and height", ranging from stars and galaxies to as small as atoms, protons, and electrons. They are all "bodies" with scales, such as microscopic particles. Small "bodies" are combined together to form the huge "body" of our world. We say that space is three-dimensional. Three-dimensional space is constantly changing, so a dimension of time needs to be added: three-dimensional space + one-dimensional time, which constitutes our universe.
We live in a four-dimensional space-time
In basic physics, there are no one-dimensional points, lines, or two-dimensional planes in the universe. All matter is composed of three-dimensional bodies. Points, lines, and surfaces are all mathematical concepts created by humans to facilitate calculations.
But there are also deep-seated problems that are difficult to solve in basic physics. There is a fundamental conflict between the " general relativity " we use to explore the macroscopic world and the " quantum mechanics " used to study the microscopic world : for microscopic particles , the gravity is too small, and you cannot use universal gravitation to explain the relationship between nuclei, and electrons; and for galaxies, the electromagnetic force is almost zero, and we cannot use the "strong force" inside the nuclei to explain the movement of galaxies. So some physicists are trying to find a "grand unified theory" that takes into account both the microscopic state and macroscopic motion of matter.
But for basic physics that has been developed for hundreds of years, string theory is a very magical theoretical framework. String theory believes that the world is simply composed of one-dimensional "energy lines". This energy line is called a "string." In other words, string theory says that the world is as small as elementary particles and as large as stars and galaxies. A bunch of lines instead of a body, which goes against our observation and understanding of the world, and is a crazy idea.
The World of String Theory
If you think that people who engage in string theory are "civilians", you are totally wrong. Basic physics originates from the observation of the material world. Physicists observe the world through various instruments, conduct various experiments, find patterns through calculations, and finally derive a series of axioms and laws. String theory scholars are all mathematicians. They first hypothesized a "string" and then used a series of extremely complex calculations to find its laws, trying to prove that basic physicists believe that "non-existent strings" can vibrate, Distortion and movement produce various microscopic particles and realize the conversion between energy and matter - strings can form "membranes", and membranes constitute the world, which has "at least ten dimensions."
Yin Xi is teaching a two-dimensional conformal field theory course
Through this clip of Yin Xi’s lecture in the 2017 "Two-dimensional Conformal Field Theory" course (this class lasts for one and a half hours), we can see that he The explanation of string theory is based on the derivation of a series of complex calculations, which is just a microcosm of string theory research.
attempts to use mathematical methods to explain all physical problems at the macro and micro levels in the universe. This is what string theorists have been trying to do. They have achieved some success, but it may take decades or decades to achieve final success. In a hundred years, it may never succeed.
But we cannot deny the achievements of Yin Xi and other physicists. They not only use various calculations to pursue the truth, but also continue to cultivate mathematical brains. These people will make contributions to mankind in many fields.
Yin Xi
Since 2013, Yin Xi has been invited to teach the summer course "Superstring Perturbation Theory" at the School of Physics, University of Science and Technology of China. Although he believes that Harvard University is the best place for him to study physics, in the future “if I come back, I will go to China with a group of physicists to develop science.”
