Yang Liming (1919.2.5—2003.1.12), a native of Lishui, Jiangsu, is a famous physicist and one of the pioneers and founders of the theoretical research of atomic nuclei in mainland China. He graduated from the Department of Mechanical Engineering of Chongqing Central University in 1942 and entered the University of Edinburgh in 1946 under the tutelage of Nobel laureate Professor Born. He received his Ph.D. in theoretical physics in 1948 and stayed on as a research assistant. He returned to China in 1951 and successively served as an associate professor at Tsinghua University, an associate professor, a professor and a doctoral supervisor at Peking University. From 1986 to 1991, he served as Chairman of the Chinese Nuclear Physics Society. In 1991, he was elected as a member (academician) of the Chinese Academy of Sciences.
Yang Liming is a famous contemporary physicist in mainland China, who has made important contributions to the formation and development of nuclear physics theory in mainland China. During his studies in the UK, he made remarkable achievements in the fields of quantization rules, fluid statistical theory, and statistical interpretation of the magic number of atomic nuclei. After returning to China, he concentrated on the study of nuclear theory, and made a series of important theoretical achievements in the frontier field of nuclear theory, which was valued and appreciated by international peers.
Determined to build dreams together in the scientific arena
In November 1991, the Chinese Academy of Sciences added 210 new academicians. Among the newly elected academicians, one husband and wife stand out: Yang Liming, a professor in the Department of Physics at Peking University, and Xia Peisu, a researcher at the Institute of Computing Technology of the Chinese Academy of Sciences.
On February 5, 1919, Yang Liming was born in a poor intellectual family in Lishui County, Jiangsu Province. When he was in high school, his hometown was unfortunately occupied by the Japanese invaders, and his family had to leave their homeland and flee to the southwest. When he was studying in Sichuan, Yang Liming's middle school was bombed by Japanese planes, and the teacher was unfortunately killed in the explosion. This experience deeply pained and shocked Yang Liming, and he realized that the reason why Japan dared to bully China so brazenly was because of their strong industrial strength. In the face of the humiliation of the country and the suffering of the nation, Yang Liming silently made a vow in his heart to learn engineering and save the country with industry. In 1938, with excellent results, Yang Liming obtained the qualification of Chongqing Central University, and he did not hesitate to choose the Department of Mechanical Engineering and embarked on the road of industrial salvation.
However, Yang Liming's hobby is not engineering but mathematics. After entering university, he gradually realized that the strength of the country is the result of the joint efforts of diverse talents. When you are young, it is important to choose the direction in which you can best play to your strengths. Looking at his own conditions and interests, Yang Liming found that physics is what he is really passionate about and good at. After graduating from university, the one-year experience of working in Kunming Central Machinery Factory made Yang Liming more determined to change his study of mathematics and physics. He then returned to his alma mater as a teaching assistant in the Department of Mechanical Engineering, while auditing and self-studying mathematics and physics. In this process, Yang Liming got acquainted with the like-minded Xia Peisu, and both of them had the dream of serving the country through industry, encouraging each other and moving forward together.
In 1944, Yang Liming passed the international student examination and was sent to study in the United Kingdom in 1945. In 1947, Xia Peisu also braved the wind and waves and came to the United Kingdom, the birthplace of modern science. Studying and working at the University of Edinburgh, Yang Liming and Xia Peisu finally ended their lives as a cowherd and weaver girl and married in 1950. In the winter of 1951, the two were invited by Zhou Peiyuan, the founder of modern Chinese mechanics and theoretical physics, to return to their motherland, and since then they have contributed all their life's enthusiasm and energy to the country, and 40 years later, they were elected academicians of the Chinese Academy of Sciences at the same time, which is a good story in the scientific world.
Until the twilight of their lives, Yang Liming and his wife still worked hard for the cause of the motherland, and made unremitting explorations in the scientific world with the spirit of seizing the day. In the late 90s of the 20th century, in order to help computer researchers solve the mystery of quantum computers, Yang Liming, who was close to his old age, spent nearly a year guiding Xia Peisu to complete a review article on quantum computing, which was widely cited in the domestic computer industry and produced a good response.
"One of the most talented, hardworking and conscientious people"
In 1945, 26-year-old Yang Liming was admitted to the UK at public expense in the name of studying engineering, and went to Manchester, England for an internship in a large factory. He used his solid knowledge accumulation to help the factory solve a design problem that had plagued him for many years, and won the favor of the factory. Yang Liming wasted no time in proposing that he did not want anything else in return, but only hoped to study for a doctorate in physics in the UK. For this request, the factory readily agreed. In 1946, Yang Liming met Professor Born, a giant of contemporary physics and one of the founders of quantum mechanics. Yang Liming's son, Yang Yuemin, once recalled the scene of Yang Liming's first meeting with Professor Born in a letter: "My father went to England to study and hoped to learn from Born as a teacher. In this way, Yang Liming won the favor of Born with his determination and ability, and entered the new atomic world.
At the University of Edinburgh, Yang Liming laid a comprehensive and solid theoretical foundation in a very short period of time with superhuman perseverance, and successfully obtained a doctorate in theoretical physics from the University of Edinburgh at the end of 1948, and continued to stay with Born as a research assistant. During this period, Yang Liming began to make a name for himself in the international theoretical physics community, and many of his research achievements were recognized by international peers. Starting from the equation of motion, he deduced for the first time the most common expressions and quantum conditions of momentum in the appearance of coordinates, which have been used by many foreign scientists. The universal formula for finding the trace of Dirac matrices derived by him in the study of quantum field theory has also been included in some monographs as theorems. Under the inspiration of Professor Born, he successfully explained the magic number in the atomic nucleus that had just been discovered at that time, which attracted the attention of the international academic community. He extended the Born-Green liquid theory to mixed liquids, and traced individual molecules in the flow under statistical descriptions to derive the diffusion coefficient.
Born spoke highly of his Chinese disciple. In the early 50s of the 20th century, he introduced Yang Liming's research results to dozens of famous physicists, including Bohr, Heisenberg, Fermi, Wegener, Jodang, and Fürth, as well as several important journals. In order to get the recognition that Yang Liming's work deserves, Born spends a lot of energy communicating and debating with other physicists. Born spoke highly of Yang's academic achievements even more so than one of the most proud doctoral protégés he had personally supervised, Goppert Meyer. Almost all of the important articles published by Yang Liming during his doctoral studies were completed with the help of Born. Born's efforts to defend Yang Liming's reasoning are no less than his own writing of several articles. When Yang Liming decided to return to China, Born also expressed his full understanding and support, and wrote to his Chinese disciples, Peng Huanwu and Zhou Peiyuan, to recommend. In a letter to Zhou Peiyuan, Born described Yang Liming as "the most talented, hardworking and conscientious man."
Professor Born's words and deeds and master's demeanor deeply touched Yang Liming. According to Yang Yuemin's recollection, when Yang Liming and Xia Peisu tied the knot in Edinburgh, Born gave a tablecloth as a wedding gift. When Yang Liming was alive, he always cherished this gift full of memories and nostalgia.
"Thus began a new page in our lives"
In October 1949, when the People's Republic of China was founded, Yang Liming and his wife, who were in a foreign country, were very excited, unable to sleep all night, and returned to their hearts like arrows. In the winter of 1950, Zhou Peiyuan visited Britain and visited Professor Born at the University of Edinburgh, and extended a warm invitation to Yang Liming and Xia Peisu to return to China. Many years later, Yang Liming can still clearly remember the mood of those years: "At that time, we already had a better working salary, but as Chinese, we wanted to go back to the motherland to participate in construction." What's more, at that time, the liberation was not long ago, and there was an urgent need for professional talents. As for the working and living conditions after returning to China, we have no special requirements, but we believe that we have the necessary professional foundation and scientific research experience to work independently anywhere. Now is the time for us to serve our motherland. So in the autumn of 1951, we boarded a passenger ship back to China, and a new chapter in our lives began. ”
After returning to China, Yang Liming first went to work in the Department of Physics of Tsinghua University, and then moved to the Department of Physics of Peking University in 1952. In Yang Liming's own words, his scientific research work after returning to China is very different from before. If the work in England is compared to "guerrilla warfare", then the work after returning home is "tackling tough battles". Yang Liming focuses on the theory of the atomic nucleus, especially the theory of nuclear many-body and the collective movement of the nuclear. And his work is in line with the new developments in nuclear physics in the world. At the end of the 50s of the 20th century, Brueckner's theory appeared internationally, which is an important development of the nuclear many-body theory. Yang Liming derived this theory through the analysis of multiple scattering in the nucleus. In the 60s, the application of the "pair correlation" theory of superconductors to the atomic nucleus promoted another important development of the nuclear theory. In 1964, Yang proposed a new method for dealing with nucleon pair interactions in deformed nuclei. This method has been widely used in related calculations. Since the 70s, Yang Liming has carried out microscopic research on the collective movement of atomic nuclei. In order to deepen the understanding of the motion law of the low excitation region of the atomic nucleus, Yang Liming proposed a systematic IBM microscopic theory. Later, he expanded the theory to successfully deal with the intrusion state of the nucleus near the full-shell nucleus. After the theory was published in the 80s, it was highly valued and appreciated by international peers.
Due to Yang Liming's outstanding achievements in the study of atomic nuclear collective states, in 1982, he was invited to give a lecture on IBM microscopic theory in Italy as a keynote speaker. In 1983, at the suggestion of international peers, he presided over the international conference on the collective state of the atomic nucleus in Suzhou; In 1985, he was invited to Yale University as a visiting scholar. In 1986, he was appointed as a visiting professor at the Technical University of Munich in West Germany. In 1987, the University of Tokyo offered to sign a cooperation agreement with the Nuclear Theory Research Group of Peking University. Yang Liming also won the first prize of the Science and Technology Progress Award of the State Education Commission in 1985 and the third prize of the National Natural Science Award in 1987 for this work.
"My wish before returning home has come true"
In the first few years after returning to China, in order to meet the needs of the country's atomic energy industry, Yang Liming spent most of his time training young teachers and graduate students. He has taught courses in atomic physics, quantum mechanics, group theory, and nuclear physics. At the end of the 50s of the 20th century, he cooperated with Academician Yu Min to hold a nationwide nuclear physics workshop. The "Lecture Notes on Nuclear Theory" co-authored by them is the earliest textbook on the theory of the atomic nucleus on the mainland and has become a classic textbook.
Yang Liming has cultivated a large number of high-level talents in theoretical physics and nuclear theory, including more than 30 doctoral and master's students, distributed all over the country, and has become the backbone of various units. When Yang Liming leads young people to carry out research work, he always gives full play to academic democracy, conducts academic discussions as equals, and encourages young people to humbly learn from the strengths of others and give full play to their own wisdom. In his later years, Yang Liming once sighed: "When I found that many of the backbone of the mainland nuclear physics community are my students, it was a great comfort to me, and my wish before returning to China really came true." ”
Yang Liming has been working quietly in the academic field, he is modest and low-key, he was promoted to professor and elected as an academician relatively late, however, his profound academic attainments and outstanding research achievements enjoy a high reputation in the international physics community. According to Yang Yuemin's recollection, Yang Liming was one of the scholars in the Asia-Pacific region authorized to recommend Nobel Prize candidates in physics, and he actively performed relevant duties. Academician Yang Liming's life is the epitome of unremitting pursuit and selfless dedication to nuclear physics research. At a party with students, he joked that he was a mythical person who had been punished by the gods and had to run without stopping. This perseverance and never-ending spirit is a true portrayal of his scientific research career. However, Academician Yang Liming's life was not all smooth sailing. Because of their dedication to work, he and his wife lost their beloved son due to negligence when they were young, which became an eternal pain in their hearts. But even so, they still stick to their scientific research posts and contribute to the scientific cause of mankind.
On January 12, 2003, Yang Liming passed away due to illness, but his lofty quality and professionalism will always live in people's hearts. His story will inspire future researchers to continue to strive for the scientific cause of mankind.