Ye Qisun

Ye Qisun a Chinese physicist and educator of the twentieth century (1898-1977) who was one of the founding figures of modern physics in China and who trained many of the scientists who later led the country's research and defence programmes.

Early Life and Education

Ye Qisun was born on 18 July 1898 in Shanghai, into a family with roots in the scholarly and commercial life of the city. Orphaned early, he was raised by relatives who valued education, and he showed a remarkable aptitude for mathematics and the physical sciences. He entered Tsinghua College, the preparatory school that sent students to the United States.

He sailed to America in the 1910s and studied at the University of Chicago and then at Harvard University, where he worked on experimental physics. He completed his doctorate in the early 1920s with research on the measurement of physical quantities of great precision, a subject that required patience and ingenuity in the construction of instruments.

His American training gave him a thorough command of experimental method and of the theories then reshaping physics, including relativity and the quantum theory of light. He returned to China determined to transplant these subjects into a country that had almost no research tradition in the field, and to build the institutions that would sustain them.

Founding a Physics Department

Ye Qisun joined the faculty of Tsinghua University in 1925 and became the head of its department of physics. He built the department almost from nothing, designing laboratories, acquiring apparatus and setting a curriculum that combined rigorous theory with hands-on experiment. He insisted that students learn to handle instruments and to think for themselves.

He gathered around him an exceptional group of young teachers and researchers, several of whom he had recruited from abroad, and he created an atmosphere of high expectation and mutual respect. The department became the leading centre of physics in China, and its graduates went on to occupy key positions in universities, institutes and national programmes.

His approach was to teach the fundamentals with great care while exposing students to the newest developments. He lectured on the theory of relativity and on the quantum theory when these subjects were still new even in Europe, and he encouraged students to read the international literature and to carry out original research rather than merely absorb received results.

Research and Scientific Work

Ye Qisun's own research lay in experimental physics and in precision measurement. He studied the properties of matter and of radiation, and he worked on problems of measurement that demanded extreme care and control of error. His papers, though not numerous, were respected for their accuracy and for the elegance of their experimental design.

He was interested throughout his career in the determination of fundamental constants and in the improvement of instruments, and he carried this interest into his teaching. He argued that physics advanced not only through bold theory but through the patient refinement of measurement, and that a country could not build a science without mastering the craft of the laboratory.

He also wrote and translated works on physics for Chinese readers, helping to establish a technical vocabulary in the Chinese language and to make the results of international research accessible to students at home. This labour of translation and exposition was indispensable to the growth of scientific education in the country.

Teacher of a Generation

The roll of Ye Qisun's students reads like a directory of modern Chinese science. Among those who studied under him were Zhao Zhongyao, Wang Ganchang, Qian Sanqiang, Zhao Jiuzhang and Wang Zhuo, physicists who became leaders of research in nuclear science, cosmic rays, space physics and optics. His department was, in effect, the nursery of the national scientific effort.

He took a personal interest in his students, supporting them in their studies abroad and in their careers, and he sheltered many of them during periods of political difficulty. His integrity and his refusal to subordinate scholarship to fashion made him a moral as well as an intellectual model for the community.

During the turmoil of the middle decades of the century he endured persecution and personal loss, including the death of his wife, yet he continued to teach and to advise. He was later honoured for his role in founding Chinese physics, and his students sought to honour their debt to him through the institutions they built in turn.

Influence and Legacy

Ye Qisun is remembered as one of the fathers of Chinese physics. The department he founded at Tsinghua became the model for physics education throughout the country, and the scientists he trained formed the core of the research programmes that produced China's achievements in nuclear science, space and defence.

He was elected to the Chinese Academy of Sciences and received official recognition for his contributions to science and education. A number of prizes, buildings and foundations bear his name, and the centenary of his birth was marked with public ceremonies honouring his memory.

He died on 13 January 1977 in Beijing. His legacy is not a single discovery or invention but a generation, and the influence of his teaching continues to shape the scientific life of the country long after his death. He is honoured as the teacher of those who made Chinese physics.

See also

• Zhao Zhongyao
• Wang Ganchang
• Tsinghua University
• Chinese Academy of Sciences