Yang Zhenning: A driving force behind Sino-US scientific and technological exchanges and cooperation

Yang Zhenning is one of the most influential theoretical physicists in the world today. In 1971, Mr. Yang returned to China to visit relatives and friends. This was not only his first trip back home after 26 years in the United States, but also a pioneering move in the history of Sino-US scientific and technological exchanges. This article focuses on the ins and outs of this major historical event. This article is selected from the "Research on the History of Natural Sciences" and has been recognized by the reviewers invited by the journal. One reviewer believes that Yang Zhenning's first visit to China half a century ago "will be proved by history to be a milestone event with far-reaching influence"; another expert pointed out that the relevant information disclosed in the article has "historical value."

Written by Liu Jinyan (Institute of the History of Natural Sciences, Chinese Academy of Sciences), Zhang Baichun (Institute of the History of Natural Sciences, Chinese Academy of Sciences, Center for the History of Science and Technology, Nankai University), Wu Yueliang (International Centre for Theoretical Physics (Asia Pacific), University of the Chinese Academy of Sciences, Institute of Theoretical Physics, Chinese Academy of Sciences)

In April 1971, China and the United States started the "ping-pong diplomacy" and began to melt the ice that had separated the two countries for more than 20 years. On July 16 of the same year, the Chinese and American governments simultaneously announced that Dr. Henry A. Kissinger (1923-), then Assistant to the President for National Security Affairs of the United States, had visited China from September 9 to 11 of that month. [1] In February of the following year, then-US President Richard M. Nixon (1913-1994) visited China. China and the United States achieved a "handshake across the Pacific", opening a new chapter in bilateral relations and having a significant impact on the international political landscape.

The reopening of the door to Sino-US exchanges 50 years ago was mainly due to the extraordinary strategic vision and political courage of Chinese and American leaders such as Chairman Mao Zedong, Premier Zhou Enlai, President Nixon, and Dr. Kissinger. During this period, the scientific communities of China and the United States seized the opportunity and actively promoted scientific and technological exchanges between the two countries. Mr. Yang Zhenning, a famous physicist and Nobel Prize winner in Physics, was an important pioneer and promoter in this regard. In 1971, he arrived in Shanghai just a few days after Kissinger's visit to China, becoming the first well-known Chinese-American physicist to visit mainland China. Since then, Yang Zhenning has worked hard to build a bridge for Sino-US scientific and cultural exchanges and mutual understanding between the peoples of the two countries. Regarding the visit to China in 1971, Yang Zhenning's articles or public speeches [Note 1] have relevant records. This article mainly focuses on the process and impact of Yang Zhenning's first visit to China in the 1970s, especially in 1971, based on historical materials such as archives, diaries, and memoirs, and shows his contributions to promoting Sino-US scientific and technological exchanges and China's scientific and technological development.

01 Ice-breaking Journey

In the early 1970s, both the Chinese and American governments were interested in improving bilateral diplomatic relations. On March 15, 1971, the United States lifted its ban on its citizens traveling to China. [Note 2][2] Yang Zhenning was keenly aware of the signs of "thawing" in relations between the two countries. Considering that he had some understanding and deep feelings for both China and the United States, Yang Zhenning believed that he had the responsibility to build a bridge of understanding and friendship between the two countries. At the same time, he learned that his father Yang Wuzhi was seriously ill and hospitalized. He was worried that the "door between China and the United States, which had just opened a small crack, might be closed again within a few months due to the Vietnam War and the changing geopolitical situation in Asia" [Note 3], so he wrote to his father to express his willingness to return to China for a visit. [3] Yang Wuzhi reported the news to the State Council, and the Central Committee of the Communist Party of China approved Yang Zhenning's application to return to China and decided: "In accordance with the consistent policy towards senior overseas intellectuals, in the spirit of warm care, highlighting politics, and doing more work to unite and win over, we should do a good job in receiving Yang." [4] In fact, Yang Zhenning's visit to China also obtained official consent from the United States. President Nixon’s science advisor Edward E. David (1925-2017) hoped that Yang Zhenning would visit China in a private capacity to explore the possibility and methods of effective contact between the Chinese and American academies of science. [5]

1.1 Itinerary

With the help of the Chinese Embassy in France, Yang Zhenning successfully obtained a visa to visit China and arrived in Shanghai on an Air France flight on the evening of July 20, 1971, returning to his motherland after 26 years away.[Note 4] Yang Zhenning's visit lasted for four weeks (July 20-August 17, 1971), and the places he visited were mainly Shanghai, Beijing and Hefei. In Shanghai, he visited the Industrial Exhibition Hall, the Jiangdi Tunnel, the Institute of Biochemistry of the Chinese Academy of Sciences, the Institute of Physiology of the Chinese Academy of Sciences, Fudan University, and the Shanghai Diesel Engine Factory. In Beijing, he visited Tsinghua University, Peking University, Beijing Petrochemical General Plant, the Institute of Atomic Energy of the Chinese Academy of Sciences, and Beijing No. 31 Middle School, as well as the Forbidden City, the Great Wall, the Ming Tombs, and the Summer Palace. He went to Hefei to visit his relatives and visited the Mao Zedong Thought Museum and Anhui Textile Factory in Hefei. In addition, Yang Zhenning also visited Dazhai Village in Xiyang County, Shanxi Province. The above-mentioned places were carefully arranged by the reception team so that Yang Zhenning could see "the spiritual outlook of the new China and the great achievements of the socialist construction of the motherland."[4]

The Chinese scientific community attached great importance to Yang Zhenning's visit. They organized the Basic Theory Research Group of the Institute of Physics of the Chinese Academy of Sciences, the Elementary Particle Research Group of the Institute of Atomic Energy of the Chinese Academy of Sciences, and the Elementary Particle Research Group of the Department of Physics of Peking University to learn about the progress of international elementary particle research and Yang Zhenning's recent work. [6] Yang Zhenning gave academic reports and held discussions with scientists in Shanghai (July 24 and August 14, 1971) and Beijing (August 3, 1971), respectively, to introduce the status of international scientific research, especially the new progress of American physics research, to Chinese scholars. His report focused on particle physics, including the principle of symmetry, the internal structure of elementary particles and the current status of elementary particle research. It also touched on the relationship between low-energy nuclear physics and high-energy nuclear physics, and the application of atomic energy in the national economy, especially in nuclear power. In addition, the reception group arranged for Li Bing'an of the Institute of Atomic Energy of the Chinese Academy of Sciences to focus on introducing the straton model proposed by Chinese physicists in 1965-1966 to Yang Zhenning. [Note 5][7]

1.2 Suggestions on scientific issues such as the construction of high-energy accelerators

The content of Yang Zhenning's discussion with Chinese scientists was relatively broad, involving institutional issues in American scientific research, the application of modern physics in science and technology, national defense, industry and agriculture, and the development of theoretical physics. In order to make full use of the limited time of his visit to China and introduce as much as possible about the development of foreign science and understand the current situation of China's development, Yang Zhenning sometimes used lunch time to communicate with scholars participating in the discussion, and even did not take a break after lunch and talked directly until the evening. During the discussion, he learned that the Chinese academic community is concerned about whether China needs to build a high-energy accelerator. His opinion is: "I think it is wrong for New China to not conduct experiments in high-energy physics at all, because high-energy physics is a very important direction and is at the forefront of physics. But now we have to do it on a big scale and catch up immediately. For example, the United States has built an accelerator with an energy of 200 billion electron volts, and you have built one with 5 The economic power is not enough to build an accelerator with an energy of 10 billion electron volts. New China has more urgent needs in other areas. The compromise is to conduct research in technology, such as superconductivity research, to train talents. These talents can also be very useful in other areas and can contribute to society. Experiments in superconducting magnets and superconducting cavities and ultra-pure aluminum can also achieve certain progress. If there is still spare capacity, it is also good to build an accelerator with an energy of 10 billion electron volts and a high beam intensity and flux. Talents can be trained, but it is difficult to conduct cutting-edge experiments. He believes that "physics is mainly based on experiments. Theoretical work is easy to be unrealistic without experiments, but the development of a country must be based on national strength." Therefore, he suggested that China should first do some research in theory and make preparations in technology. After the industrial base is developed, "work can be done to catch up." [8]

On August 10, 1971, Yang Zhenning again talked about the application of elementary particles during a discussion at Peking University. He believed that: "From the current situation in China, many aspects need to be developed. A few people can do it, but it is not reasonable to spend a lot of manpower to study elementary particles. ... China's united efforts may be the most suitable way to achieve a practical goal rather than a theoretical goal. For example, it is very necessary for the country to focus all its work on high-speed, large-scale computers. Because this is one of the most important developments of mankind in the 20th century, China cannot lag behind forever - this requires all kinds of talents, and if many people are absorbed, there will not be much spare energy for other aspects. There are many by-products here, and there must be important progress in semiconductor theory and experiments, materials, and magnetic research." However, he "firmly believes that elementary particle research will have unimaginable applications in the future." [9] He also suggested that China should attach importance to theoretical research, vigorously develop semiconductor and laser research, and develop low-temperature physics, superconductors, vacuum technology and theoretical mathematics. [9]

Yang Zhenning noticed China's achievements in artificial synthesis of crystalline bovine insulin and acupuncture anesthesia. He believed that "the achievement of synthetic bovine insulin is amazing and remarkable, with great international impact and great contribution to mankind." For this reason, he intended to recommend artificial synthesis of crystalline bovine insulin to win the Nobel Prize in Chemistry. [10] He advocated that the medical community should increase its scientific research efforts several times to study the theory of acupuncture anesthesia. In addition, he suggested that China resume publishing academic journals as soon as possible, believing that writing articles would not only help researchers organize their ideas, but also promote academic exchanges. [Note 6] He also talked about the intention of Robert Wilson (1914-2000), director of the Fermi National Accelerator Laboratory in the United States, to invite Chinese scientists to participate in the laboratory's research work. Cornell University and the State University of New York also asked how to invite Chinese scientists to participate in the physics conference held in August and September 1971. [11]

1.3 Meeting with teachers and friends and being received by Premier Zhou Enlai

Yang Zhenning met his father-in-law General Du Yuming for the first time in Beijing. He was also invited to a banquet by Wu Youxun, Vice President of the Chinese Academy of Sciences, Zhang Wenyu, Deputy Director of the Institute of Atomic Energy of the Chinese Academy of Sciences, and scientists Deng Jiaxian and Hua Luogeng [Note 7]. He also met Zhou Peiyuan, Wang Zhuxi, Zhao Zhongyao, Huang Kun, Huang Wan [Note 8], Wang Chengshu, Qian Xuesen and other teachers and friends. When meeting Wu Youxun, Yang Zhenning said that after returning to China, he realized that the spirit of the People's Republic of China was what Chairman Mao said in his poem: "For the sake of sacrifice, there are many ambitions, and we dare to change the sun and the moon into a new sky." He expressed to Wu Youxun that he was asked by David, the science adviser to the US President, to explore the possibility of contact between the Chinese and American academies of science. Finally, with the approval of the Ministry of Foreign Affairs, Liu Xiyao, the liaison officer of Premier Zhou Enlai at the Chinese Academy of Sciences, replied to Yang Zhenning: Since China and the United States do not have diplomatic relations yet, it is inconvenient to have such contact, but the request of individual American scientists to visit China can be considered. Yang Zhenning provided a list of scientists for reference. [Note 9][13]

At 7:00 p.m. on August 4, 1971, Premier Zhou Enlai met with and hosted a banquet for Yang Zhenning at the Great Hall of the People.[Note 10] The event lasted nearly five hours. Premier Zhou was concerned about Yang Zhenning's visit to China and talked with him about the international situation and the social and political situation in the United States, including the organizational form and school-running policies of American universities, as well as academic movements and racial issues. After the meeting, Yang Zhenning excitedly told his brother Yang Zhenhan and sister Yang Zhenyu that he had never thought that the Premier of the People's Republic of China was so busy that he could spend so much time talking to him. The next morning, on his way to Zhoukoudian to visit the exhibition hall of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Yang Zhenning told Yue Daiheng, the head of the Tourism Bureau: "The Premier is so busy, but he cares about everything, big or small. He even knows everything about my activities in Beijing and Shanghai. I am very surprised that Premier Zhou is already 73 years old, but he is still in such good spirits."[15]

Yang Zhenning was deeply impressed by meeting his close friend Deng Jiaxian after 22 years of separation. Before returning to China, he specifically proposed to meet Deng Jiaxian. Previously, Yang Zhenning learned from American newspapers that Deng Jiaxian might be an important leader in China's nuclear weapons industry. Arranged by Premier Zhou, Deng Jiaxian returned to Beijing to accompany Yang Zhenning to participate in many activities. On the evening of August 11, when Yang Zhenning returned to Shanghai from Beijing, he asked Deng Jiaxian at the airport before leaving whether Han Chun (Joan Hinton, 1921-2010) [Note 11], who had participated in the development of the first atomic bomb in the United States, had participated in the development of China's atomic bomb. Deng Jiaxian said he didn't know. Yang Zhenning asked Deng Jiaxian to let him know after understanding the situation, and left Deng Jiaxian his address and phone number in Shanghai [Note 12]. Deng Jiaxian reported the situation to the National Defense Science and Technology Commission. After consultation with the reception group, the National Defense Science and Technology Commission suggested that Deng Jiaxian write a letter to Yang Zhenning to tell him about Han Chun. The night before returning to the United States, Yang Zhenning was treated to a banquet by the leaders of the Shanghai Municipal Party Committee. During the dinner, the reception team gave Yang Zhenning a photo of Premier Zhou Enlai meeting him and handed him a letter from Deng Jiaxian. In the letter, Deng Jiaxian told Yang Zhenning that Han Chun did not participate in any work related to China's nuclear weapons manufacturing.[18] In the letter, Deng Jiaxian expressed the hope that Yang Zhenning would often think of his motherland while abroad, and expressed his farewell feelings with the words "I worry about my friends even when they are thousands of miles apart" and "I hope we can live long and share the same path." Yang Zhenning was deeply moved after reading the letter and burst into tears.[10] 50 years later, at the "Mr. Yang Zhenning Academic Thought Seminar - Celebrating Mr. Yang's 100th Birthday" hosted by Tsinghua University, the Chinese Physical Society, and the Chinese University of Hong Kong on September 22, 2021, Yang Zhenning responded affectionately, saying: "Jiaxian, I understand what you mean by 'share the same path'. I can confidently tell you that my next 50 years will be in line with your expectations of 'share the same path', and I believe you will be satisfied."[19]

On the morning of August 17, Yang Zhenning took an Air France flight back to the United States. According to the plan, Yang Zhenning's visit to China was not to be made public. However, the Hong Kong Star and the New York Times reported Yang Zhenning's visit to China on August 7 and 8, 1971, respectively, and believed that his visit to China might be related to President Nixon's upcoming visit to China. [20] In order to avoid rumors and to prevent his wife from worrying, Yang Zhenning proposed that China make the news of his visit to China public. On August 10, 1971, the People's Daily published a short message: "Dr. Yang Zhenning, a Chinese-American physicist, returned to Shanghai in late July to visit his sick father and is currently visiting Beijing." On August 19, the People's Daily published the news that Yang Zhenning had left Shanghai and briefly introduced his itinerary for this visit to China. [21] On August 21, Zhu Kezhen, vice president of the Chinese Academy of Sciences, recorded in his diary his and Ge Tingsui's personal views on Yang Zhenning's visit to China and the high-level courtesy he received (reference [14], page 457).

02 Introducing China after returning to the United States and subsequent visits to China

Yang Zhenning's visit to China attracted widespread attention. After he returned to the United States, Chinese scientists such as Chen Xingshen, Lin Jiaqiao, and Ren Zhigong called him, hoping to learn about the real situation in China from his personal experience. On September 17, 1971, Yang Zhenning wrote to his father Yang Wuzhi: "The interest of all walks of life in the new China is simply beyond description. I have turned down all requests for interviews from reporters, television, and radio. ... The interest of all walks of life in the new China is a good phenomenon. I hope that friendship between the Chinese and American people will be built from this. If the diplomatic community and academic groups invite me to a forum, I may participate. My visit to the new China has had a considerable impact on the feelings of the Chinese people here." [22]

2.1 Introducing China and its technological development to all sectors of the American community

After returning to the United States, Yang Zhenning actively gave public speeches on various occasions, introducing the achievements made after the founding of the People's Republic of China, which had a wide influence on senior intellectuals studying in the United States. For example, on August 25, 1971, he gave a speech at a physics conference at Cornell University. The audience included participants and Cornell University teachers and students. Among them, the Soviet physicists present took notes desperately. One even joked with Yang Zhenning: "You may never get a visa to the Soviet Union again." [22] On September 21, Yang Zhenning gave a speech entitled "My Impression of the People's Republic of China" at the Stony Brook University of the State University of New York where he taught. The audience was about 1,400. He believed that although China was still poor, lacked material wealth, and its industrial technology was also backward, the focus of the change in China today compared with 26 years ago was "spiritual" - the spiritual outlook of the Chinese people had changed greatly. [22] In November, Physics Today published an interview with senior editor Gloria B. Lubkin (1933-2020) with Chen Ning Yang on the current situation in China. The content covered "Chinese physics", "accelerators", "scientific plans", "physics research and factories" and "Chinese spirit". [23]

From February 21 to 28, 1972, Nixon successfully visited China. On February 28, China and the United States jointly issued the "Joint Communiqué of the People's Republic of China and the United States of America" ​​("Shanghai Communiqué"), announcing the normalization of Sino-US relations. This visit was called a "De Gaulle-style visit" by Yang Zhenning [Note 13]. During Nixon's visit to China, Yang Zhenning wrote in a letter to his father Yang Wuzhi: "'There are so many things, and they are always urgent. Ten thousand years is too long. We must seize the day.' This is a line from Chairman Mao's poem that President Nixon quoted when he spoke at a banquet in the Great Hall of the People a few hours ago. 'The four seas are turbulent', 'the five continents are shaking', these days' current events are of epoch-making significance and have incomparable significance for the American people to correctly understand the new China." The letter also mentioned that "the 'star spangled banner' and 'people who rise up and refuse to be slaves' brought infinite excitement to Zhili [Note 14] and me who grew up during the War of Resistance." [25] On March 21, Yang Zhenning gave an informal speech at the State University of New York at Stony Brook. His talk involved his interpretation of the Shanghai Communiqué, Sino-US-Soviet relations, the future of China's Taiwan region, and the significance of the achievements made after the founding of the People's Republic of China to the development of human history. The talk was later published in the Chinese journal Stony Brook News, which was run by Chinese students at Stony Brook University, under the title "Some Discussions on the Current Situation". It was then reprinted by China's Reference News. On April 17, Yang Zhenning wrote to his father, asking him not to worry about his speech being attacked. The letter said: "I am speaking the truth, so I am not afraid of being attacked. ... Although being attacked is inevitable, it is not in line with the standard of being a human being to shrink from it. If Sino-US relations deteriorate greatly, is there a danger that a phenomenon like J. Mecarthy[Note 15] will reappear? Of course it is very possible. Not recognizing this point means that I do not have a thorough understanding of American society, but recognizing this does not mean that I should shrink from it. Please forgive me." [25]

2.2 Second visit to China

In order to gain a deeper understanding of China and to more comprehensively introduce the situation in China to overseas Chinese and the American people, Yang Zhenning returned to China again from June 16 to July 21, 1972 to visit relatives and sightsee. In addition to visiting Shanghai and Beijing, he also visited Nanjing, Shashiyu Village in Zunhua City, Hebei Province, Xi'an, Yan'an and Hangzhou. During his stay in Shanghai (June 16-22), Yang Zhenning visited his father Yang Wuzhi in the hospital for an hour and a half almost every day. In addition, he visited the Shanghai Children's Palace, the site of the First National Congress of the Communist Party of China, the Shanghai Machine Tool Factory, the Natural History Museum and the Ninth Chemical Fiber Factory[26]. In Nanjing, Yang Zhenning visited the Yangtze River Bridge, the Observatory, Nanjing University, the Sun Yat-sen Mausoleum and the Arts and Crafts Exhibition[27]. In Beijing, in addition to visiting the Nationalities College, the zoo, the Yangcun Army, the Forbidden City, and the Beijing Material Factory, Yang Zhenning also gave four special reports at Peking University, titled "On the Development of High-Energy Physics" (June 27), "Gauge Fields - A New Definition" (July 1), "Some Strict Solutions of Statistical Mechanics" (July 3), and "Symmetry Principles in Physics" (July 5), and discussed issues such as high-energy accelerators [Note 16] and lasers. [28] Among them, the report on gauge fields inspired Lu Qikeng of the Institute of Mathematics of the Chinese Academy of Sciences to study the correspondence between gauge fields in physics and connection theory on principal fiber bundles in mathematics.

During Yang Zhenning's second visit to China, Premier Zhou Enlai specifically instructed that "the conversation should be more in-depth" when receiving Yang Zhenning.[27] To this end, the reception team required a more in-depth and detailed reception in terms of politics and professional aspects, taking into account Yang Zhenning's wide range of interests and his characteristics as both a scientist and a social activist. In addition, the reception plan also proposed to have in-depth discussions with Yang Zhenning on issues that he was concerned about through Zhang Wenyu, Deng Jiaxian, Huang Wan, Huang Kun, etc. [27] On the evening of July 1, Premier Zhou Enlai met with and hosted a banquet for Yang Zhenning.[Note 17] During the talks, in addition to exchanging views on issues such as the US election and the Vietnam War situation as well as scientific research issues, Yang Zhenning also mentioned that scientific theoretical research should be emphasized and stressed the necessity of academic exchanges; he also proposed to establish an effective scientific management organization to cultivate scientific talents and give full play to the role of existing scientific talents. [29] Premier Zhou agreed with Yang Zhenning’s suggestion: “Mr. Yang said that our theory is too poor and we don’t communicate with others. I’m afraid this makes sense. You have seen our problem.” He also mentioned that “there are two reasons why our theory has not improved. One is that we cannot summarize our experience, return to practice, and improve it. The other is that we are not very interested in other people’s experience and fail to listen and observe more. We should listen to your good opinions and we should be able to learn something. We should not be arrogant and refuse to listen to your opinions; or we should accept them superficially and not care about them after you leave. You enthusiastically pointed out some of our shortcomings. If we just ignore them, it would be very dangerous. I am afraid that our older generation of scientific workers will be like this.” [30] Two weeks later, when meeting with a delegation of Chinese American scholars and all members of the visiting delegation of Chinese American scholars who were visiting China, Premier Zhou instructed Zhou Peiyuan to run Peking University’s science education well and improve the level of basic theory. [31] On October 6, Zhou Peiyuan published an article entitled “Some Views on the Revolution of Science Education in Comprehensive Universities”, calling for “both engineering and science, application and theory must be given importance, and neither should be neglected. … Science departments in comprehensive universities should pay sufficient attention to the research of basic theories.” [32] However, due to the interference and obstruction of the ultra-leftist ideology prevalent during the “Cultural Revolution”, most of the specific support measures for basic research by the state were not implemented. It was not until six years later that the Institute of Theoretical Physics of the Chinese Academy of Sciences was finally established in June 1978 under the personal instruction of Vice Premier Deng Xiaoping, which demonstrated the importance the Chinese government attached to basic research.

During his return to China, Yang Zhenning also met theoretical physicist Zhou Guangzhao. Yang Zhenning first heard Zhou Guangzhao's name in the late 1950s, and at that time "everyone in the field of high-energy physics in the United States knew that he was a young Chinese researcher, the most outstanding physicist with the most innovative ideas at the time." [33] At that time, Zhou Guangzhao was working at the Joint Institute for Nuclear Research in Dubna, the Soviet Union, and achieved influential results such as proving the partial conservation law of pseudovector flow. He was regarded by his American peers as the "most outstanding young scientist" of the Joint Institute for Nuclear Research. In February 1961, Zhou Guangzhao returned to China to participate in the theoretical preliminary research of the atomic bomb, and did not publish any academic papers for more than ten years. When Yang Zhenning visited China in 1971, he still asked to meet Zhou Guangzhao. The reception plan of the Ministry of Foreign Affairs at that time was "if the person is in Beijing, he can be arranged" [4]. However, Yang Zhenning did not meet Zhou Guangzhao at the banquet hosted by Premier Zhou. So he specifically mentioned Zhou Guangzhao to Premier Zhou. When he visited China for the second time, he finally met Zhou Guangzhao at a banquet hosted by Premier Zhou. From then on, they became close friends and jointly promoted the development of Chinese physics. For example, in the early 1980s, Yang Zhenning suggested to Zhou Guangzhao that China should carry out theoretical and experimental research on free electron lasers. To this end, Zhou Guangzhao guided students to investigate and carry out related research, and also discussed with experts such as Wang Ganchang, Xie Jialin, Fang Shouxian, and Yu Lihua.

2.3 Subsequent visits to China

Since 1972, Yang Zhenning has visited China almost every year. In May 1973, he returned to China for the third time to visit his father who was critically ill. In July of the same year, he returned to China for the fourth time. On the afternoon of July 17, Chairman Mao Zedong met with Yang Zhenning at his residence in the swimming pool of Zhongnanhai[34]. Premier Zhou Enlai and Zhou Peiyuan also accompanied him. Chairman Mao and Yang Zhenning discussed physics and philosophical issues such as the infinite divisibility of matter and the conservation of parity[Note 18]. Mao Zedong said: "Matter is infinitely divisible. If matter becomes indivisible after being divided to a certain stage, then what will scientists do ten thousand years from now? Some people say that Gongsun Long is a sophist, and so is Hui Shi. But there is a saying that 'a one-foot long stick can be cut in half every day, and it will never run out for ten thousand years', which means that matter is infinitely divisible. ... Parity is conserved, but it is not conserved. I support parity conservation and not conservation. I am a politician and do not understand science." Their conversation also touched on Mao Zedong's poems (such as "The Long March"), Qin Shihuang, and the Legalists in history. Mao Zedong emphasized: "The principle of the Legalists is to value the present and despise the past, to advocate social progress, to oppose the path of regression, and to move forward." (Reference [30], p. 607) At the end of the meeting, Mao Zedong said to Yang Zhenning: "Thank you, a natural scientist, for your contribution to the world." [35] This was the first time Mao Zedong met with a well-known Chinese American scientist in the 1970s, which showed his emphasis on scientific work and his concern for overseas Chinese.

From June 3 to 29, 1974, Yang Zhenning returned to China for the fifth visit. He gave lectures entitled "Integral Form of Gauge Field" and "Special Solutions of Passive Gauge Field" at Fudan University on June 7 and 14, respectively. During the visit, Yang Zhenning said that a paper on gauge field that he had recently completed during his visit to the Institute of Theoretical Physics at the University of Wrocław in Poland needed to be supplemented with some mathematical calculations, involving issues such as general relativity and differential geometry, and he was willing to discuss with researchers from Fudan University and jointly publish this paper. [36] Subsequently, he collaborated with mathematicians such as Gu Chaohao to conduct research on differential geometry of gauge field, which promoted the research on gauge field theory in the Chinese mathematics and theoretical physics community. During the collaborative discussion, Yang Zhenning constantly introduced new directions in theoretical physics and mathematics (such as mathematical problems of gauge field and soliton theory) to them, which had a profound impact. Since then, Yang Zhenning has also carried out academic cooperation with researchers from many universities or institutes, including Lanzhou University, Sun Yat-sen University, Nankai University, Tsinghua University, and the Institute of Theoretical Physics of the Chinese Academy of Sciences, which in turn influenced the exchanges and cooperation between Chinese and American universities.

2.4 Promoting Sino-US scientific and technological exchanges

Yang Zhenning's visit to China resonated with a group of senior Chinese intellectuals and strongly promoted the exchange between the scientific communities of China and the United States.[Note 19] In May 1972, the president of the American Association of Scientists and high-energy physicist M. Goldberger was invited to lead a delegation of American scientists to visit China for three weeks to investigate the development of Chinese physics.[37] From the end of June to mid-July of the same year, physicist Ren Zhigong and mathematician Lin Jiaqiao organized a "Chinese-American Scholars Visiting Group" to return to China for a visit.[38] The delegation consisted of 27 people (including 12 scholars and 15 family members). It was the first Chinese-American scholars to return to China after the founding of the People's Republic of China. They were received by Premier Zhou Enlai and other government leaders. Directly influenced by Yang Zhenning, Huang Kexun of the Massachusetts Institute of Technology visited China for the first time in early 1973. In the summer of 1971, Huang Kexun was visiting the Deutsches Elektronen-Synchrotron in Hamburg. When Huang Kexun received a Chinese letter from Yang Zhenning saying, "I am about to board a flight to Beijing," he said, "It was a powerful and thrilling moment." [39] Huang Kexun met physicists Hao Bolin and Yu Lu during his visit to China in 1973. He learned that Hao Bolin and Yu Lu were studying Wilson's paper on phase transition renormalization groups. So, after returning to the United States, Huang Kexun asked Wilson to send Hao Bolin a preprint of his and his collaborators' review article. This was six months earlier than the time it took China to obtain the latest international literature at the time, allowing them to keep up to date with the latest progress of international peer research.

In addition to American scientists visiting China, China also actively selected scientists to visit the United States. In May 1973, Zhang Wenyu, then director of the Institute of High Energy Physics of the Chinese Academy of Sciences, led a high-energy physics delegation to visit the United States. In addition, Chinese scientists also visited the Fermi National Laboratory and Brookhaven National Laboratory in the United States. From January 5 to 12, 1980, an international particle physics conference was held in Conghua County, Guangdong Province, with a total of 97 Chinese physicists and 51 Chinese particle physicists working abroad participating. This was the first international physics academic conference held in China after the end of the "Cultural Revolution". The success of the conference was inseparable from the active promotion of Yang Zhenning and Li Zhengdao [Note 20]. In the same year, Yang Zhenning planned, founded and presided over the "Committee on Education Exchange with China" at the State University of New York at Stony Brook. Using funds raised from the United States and Hong Kong, China, he sponsored 83 scholars from Chinese scientific research institutions to visit and exchange with the university over a period of 12 years. [41]

In 1978, Yang Zhenning served as the president of the Chinese American Association. Since then, he has made more contributions to the communication and exchanges between China and the United States. On January 1, 1979, China and the United States formally established diplomatic relations. Soon after, at the invitation of US President Jimmy Carter (1924-), Vice Premier Deng Xiaoping visited the United States, becoming the first government leader to officially visit the United States after the founding of the People's Republic of China. During the visit, the Chinese American Association led by Yang Zhenning organized a grand banquet to welcome Deng Xiaoping. In his speech at the banquet, Yang Zhenning emphasized the special responsibility of Chinese Americans to promote understanding and friendship between China and the United States: "We are deeply aware that because we are rooted in the culture of the two great nations of China and the United States, we have a special responsibility to promote friendship and understanding between the two countries. On this occasion today, the Chinese American Association and Chinese people from all walks of life in the United States reiterate that we will continue to do our part to build a bridge of friendship between the two great nations. We know that without this bridge, there can be no real peace and stability in the world." [42]

03 Conclusion

Yang Zhenning is not only a scientist who has made outstanding contributions to the development of world physics, but also a social activist with strong patriotic sentiments. In 1957, he and Tsung-Dao Lee won the Nobel Prize in Physics for proposing the principle of parity non-conservation under weak interactions, helping "the Chinese people change their mentality of being inferior to foreigners" [43]. In 1971, when Sino-US relations had thawed but diplomatic relations had not yet been formally established, he decisively visited China, making a significant contribution to Sino-US scientific and technological diplomacy, which was also a "turning point in his career" [44]. This "ice-breaking trip" was exemplary and had a profound impact on Sino-US scientific and technological exchanges, and has important practical significance for promoting Sino-US scientific and technological exchanges today.

Yang Zhenning has always been concerned about the development of Chinese science and technology, especially basic research, talent training, and international exchanges and cooperation, and has provided good advice to Chinese leaders and scientists. In 2003, he officially returned to Tsinghua University as a full-time professor and headed the Center for Advanced Studies at Tsinghua University. He has made outstanding contributions in leading the development of Chinese physics, cultivating young talents, and promoting research in the history of science.[45] On April 1, 2015, Yang Zhenning renounced his American citizenship and officially resumed Chinese citizenship. This was an extraordinary event, just like his first visit to China that year, reflecting China's trend of shifting from talent outflow to talent return.

Acknowledgements: Thanks to the editor-in-chief of "Research on the History of Natural Sciences", Researcher Zou Dahai, deputy editor-in-chief, Researcher Sun Lie, executive deputy editor-in-chief of "Bulletin of the Chinese Academy of Sciences", and relevant anonymous experts and leaders for reviewing the manuscript and providing suggestions for revision!

Notes to editors:

This article is authorized to be selected from the Journal of the History of Natural Sciences, Vol. 40, No. 3 (2021): pp. 374-386. On September 22, 2021, the "Symposium on Mr. Yang Zhenning's Academic Thoughts - Congratulations on Mr. Yang's 100th Birthday" was held at Tsinghua University. In his speech, Mr. Yang reviewed the fragments of his visit to China that year. At the seminar that day, the author of this article presented the preprint to Mr. Yang and provided it to some experts at the meeting for comments. Before the official publication, the author revised it again and added relevant content.

Yang Zhenning has long attached importance to and personally engaged in the study of the history of science. In January 1996, the Institute of the History of Natural Sciences of the Chinese Academy of Sciences hired Mr. Yang as an honorary researcher. The second issue of the Journal of the History of Natural Sciences reported on Mr. Yang's point of view in his impromptu speech: "The development of modern science and technology is closely related to the situation in the world in the 20th century. Therefore, in order to understand the development of the world in the 20th century and to look forward to the prospects of the 21st century, we must have a correct understanding of the history of the development of science and technology." The academic value of this assertion is worth cherishing by scholars of the history of science and technology.

Notes

1. For example, in the "Visit to China" section of Yang Zhenning's speech at the 20th Anniversary Lecture of the Chinese University of Hong Kong on March 2, 1983, he briefly introduced his visit to China in 1971.

2. On March 16, 1971, The New York Times published a news article titled “US Lifts Ban On China Travel” in a prominent position on Page 2. The article mentioned that “the United States today lifted its ban on Americans traveling to communist China and announced that it is working through private diplomatic channels to get Beijing’s ambassador to return to the Warsaw talks that were interrupted more than a year ago. Both steps are part of the Nixon administration’s ongoing policy of seeking to improve relations with China, but the State Department acknowledged that it does not expect a quick response here.”[2]

3. In Yang Zhenning's view, China and the United States were trying to see if there could be some useful contacts based on the international situation at the time. However, considering that the Vietnam War had not yet ended, Yang Zhenning was worried that the door that had just been opened might close again.

4. Yang Zhenning attached great importance to this return trip to China. He arrived in Paris 3 days in advance to wait for a visa to visit China. Since China and the United States had not yet established diplomatic relations, the visa was just a piece of paper at that time.

5. Before returning to China, Yang Zhenning did not know the specific work of the straton model. In order to help him understand the straton model in depth and to have a basis for introducing the straton model after returning to the United States, Zhou Peiyuan and Zhang Wenyu suggested giving him three papers read by Chinese physicists at the 1966 Summer Physics Conference.

6. After 1972, scientific journals such as Science in China and Acta Physica Sinica gradually resumed publication, publishing the latest research results in China. This was related to Yang Zhenning’s suggestion at the time.

7. In order to avoid having senior colleagues such as Wu Youxun greet him at the airport, Yang Zhenning specifically told the reception staff in Shanghai not to inform them of the specific time of his arrival in Beijing. He said that he would visit them immediately after arriving in Beijing. [12]

8. Huang Wan was Huang Kun’s second brother. At that time, he was the deputy director of the First Department of the General Hospital of the Chinese People’s Liberation Army (i.e. 301 Hospital).

9. There are 9 people on this list (the first 7 of whom are familiar with Yang Zhenning), including: George Kennen, professor at the Institute for Advanced Study in Princeton, one of the leaders of US foreign policy from 1945 to 1950; Jerome Wiesner, president of the Massachusetts Institute of Technology, former science adviser to President John F. Kennedy; Fred Seitz, president of Rockefeller University, former president of the American Academy of Sciences; George Wald, professor of biology at Harvard University and Nobel Prize winner; J. Watson, chairman of International Business Machines Corporation (IBM); David Rockefeller, chairman of Chase Manhattan Bank; Kerson Huang, professor of physics at the Massachusetts Institute of Technology; Jerome Cohen, professor of law at Harvard University (very friendly to the People's Republic of China, and worked hard to improve Sino-US relations); Avram N. Chomsky, professor of linguistics at the Massachusetts Institute of Technology and a leader in anti-Vietnam War thought.

10. Yang Zhenning visited the Great Wall and Ming Tombs during the day. When Yue Daiheng, the head of the Tourism Bureau, informed him that Premier Zhou would meet and entertain him that evening, Yang Zhenning was extremely excited. Accompanying Yang Zhenning to the meeting were Guo Moruo, Wu Youxun, Zhu Kezhen, Liu Xiyao, Qian Xuesen, Zhu Guangya, Zhou Peiyuan, Hua Luogeng, Ding Jiang, Zhang Wenjin, Fu Zuoyi, Du Yuming and his wife, Yang Zhenning's younger brother Yang Zhenhan and younger sister Yang Zhenyu. Zhu Kezhen recorded the following in his diary: "Premier Zhou came at 7:30 pm. We sat on rattan chairs arranged in a horseshoe shape and talked for half an hour. At about 8:00, we had dinner at a large table in the Xinjiang Hall. At the same time, Premier Zhou and Yang continued their conversation. During dinner, I sat next to Mr. Guo and Zhu Yongxing (from the Foreign Affairs Office) and could see the notes, so I knew what they were talking about. After dinner, it was already 10 o'clock, and we continued the conversation on the rattan chairs until 11:35. We talked about a wide range of topics. In general, Premier Zhou wanted to understand the domestic situation in the United States, such as everyone's impression of Kissinger, the power of the Pentagon and capitalists. The Premier said that Rogers had been playing double game with Taiwan recently. Yang had been in the United States for a long time, so he had a clear understanding of the situation. Premier Zhou asked him to come back once a year, and also mentioned the past Sino-Indian war. Yang said that Maxwell's book on the Sino-Indian war had a great influence, etc."[14]

11. Han Chun received a master's degree from the University of Wisconsin in 1944 and participated in the manufacture of enriched uranium generators in the Manhattan Project. From 1946 to 1948, Han Chun studied for a doctorate under the guidance of Enrico Fermi at the University of Chicago. During this period, she met Yang Zhenning and worked together in the same laboratory for nearly 20 months. In March 1948, Han Chun arrived in Shanghai. She arrived in Yan'an via Beijing in January 1949 and married her boyfriend Yang Zao, who arrived in Yan'an three years earlier, in April of that year. Since then, Han Chun and Yang Zao have lived in China and made contributions to agricultural mechanization. On July 24, 1971, Premier Zhou Enlai met with Han Chun, Yang Zao and his wife, as well as Han Chun's brother Han Ding's family and other American friends, and introduced their views on Sino-US talks, China's entry into the United Nations, and Taiwan. On August 7, Yang Zhenning met his classmate Han Chun when he visited Dazhai and asked her in person whether she participated in China's atomic bomb development. Han Chun said that she did not participate in this work.

12. According to Yang Zhenning's recollection: After the explosion of China's atomic bomb, he paid special attention to two American newspaper news. One news was that Deng Jiaxian was one of the main leaders in designing China's first atomic bomb, and the other news was that an American physicist (referring to Han Chun) helped China make the atomic bomb. Yang Zhenning believed the first news, but needed to learn more about the second news and hoped that this news was not true. He was eager to confirm whether China's atomic bomb was independently developed. Yang Zhenning mentioned that "the atomic bomb was made by the Chinese themselves. I don't know if today's young people understand this mentality. When I grew up, when my father's generation grew up, China was bullied by foreigners because the Chinese did not have modern (advanced weapons). So I hope that China's first atomic bomb is only made by the Chinese themselves." - The above content is compiled according to "Mr. Yang Zhenning's Family and Country Feelings" on CCTV. Chinese International (Asia) Channel on September 23, 2021.

13. Yang Zhenning mentioned in the relevant article that he heard that General Charles de Gaulle (1890-1970) had originally planned to visit China, but died before the scheduled date. When de Gaulle died, Chairman Mao sent a telegram of condolence to Mrs. de Gaulle, "I would like to express my sincere condolences and respect for him, an indomitable fighter against fascist aggression and for the protection of French national independence." In Yang Zhenning's view, the Chinese people admired de Gaulle very much, and also admired Chairman Mao's far-sighted evaluation of de Gaulle's historical contributions. Yang Zhenning also found that the talks he heard in China about Nixon's future visit to China, although tough on the surface, contained implicit admiration for his vision. Therefore, he called Nixon's visit to China a "de Gaulle-style visit to China." [24]

14. Zhili refers to Yang Zhenning’s wife Du Zhili.

15. In the original document, McCarthy's English last name was misspelled. The correct spelling is McCarthy.

16. On the afternoon of July 4, Yang Zhenning held a discussion at the Beijing Hotel on the "Development Direction of High-Energy Physics" with more than 30 scholars from the Institute of Atomic Energy, Institute of Physics, Peking University, National Defense Science and Technology Commission and other institutions. At this meeting, Yang Zhenning once again expressed his personal opinion on the construction of high-energy accelerators. He believed that from a technical point of view, China does not necessarily have to build a large high-energy accelerator. But it can build some small and medium-sized accelerators and do some basic work on accelerator principles, detection technology, etc. He also believed that cultivating a large number of talents with extensive basic theoretical knowledge is a key issue for China's scientific and technological development. [28]

17. According to the records in the archives of the Chinese Academy of Sciences, Premier Zhou Enlai met with Yang Zhenning on July 1, 1972. This is inconsistent with the date of July 2 recorded in the Chronicle of Zhou Enlai (1949-1976) (Part 2). Others who attended the meeting included Guo Moruo, Liu Xiyao, Qiao Guanhua, Zhu Kezhen, Wu Youxun, Chi Qun, Zhou Peiyuan, Zhang Wenjin, Zhang Wenyu, Wang Chengshu, Qian Weichang, Deng Jiaxian, Zhou Guangzhao, Huang Kun and Huang Wan. Du Yuming and his wife, his younger brother Yang Zhenhan and his younger sister Yang Zhenyu also attended the meeting and the banquet. [29]

18. As early as January 15, 1955, Mao Zedong discussed with physicist Qian Sanqiang whether matter is infinitely divisible. In 1963, he resonated with Japanese physicist Shoichi Sakata (1911-1970) on the conscious use of dialectical materialism in scientific research. In August 1964, Mao Zedong discussed with philosophers and physicists the issue of the infinite divisibility of matter and his views on the dialectics of nature. This directly influenced the research direction of the Chinese particle physics community, especially the straton model proposed by Chinese particle physicists in 1965-1966. [7]

19. Yang Zhenning later admitted that he did not understand what the "Cultural Revolution" was all about, and even self-deprecatingly called himself a "bad journalist."

20. The Guangzhou Conghua Particle Physics Conference was intended to expand international academic exchanges, promote the development of Chinese particle physics theory, and accumulate experience for organizing larger international conferences in the future. In April 1979, Qian Sanqiang, the chairman of the conference preparatory committee, invited Yang Zhenning and Li Zhengdao. They both gladly accepted the invitation and actively recommended and contacted overseas Chinese and Chinese physicists in Taiwan and abroad to attend the conference. [40]

References

［1］ Announcement[N]. People’s Daily, 1971-07-16(01).

［2］ US Lifts Ban on China Travel[N]. The New York Times, 1971-03-16(02).

[3] Yang Zhenning. The significance of Sino-US scientific and technological exchanges to Chinese scientists (1976) [M]//Forty years of reading and teaching. Hong Kong: Joint Publishing Company, 1985: 13-14.

[4] About the plan to receive Yang Zhenning [A]. Archives of the Chinese Academy of Sciences

[5] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 11 [A]. Archives of the Chinese Academy of Sciences

[6] Letter from Zhou Peiyuan and Zhang Wenyu to Guo Moruo and Liu Xiyao [A]. Archives of the Chinese Academy of Sciences

［7］ LIU J Y. Chinese physicists' construction of the straton model in social context[J]. Chinese Annals of History of Science and Technology, 2018, 2(1): 85-122.

[8] Academic report by Chinese-American physicist Chen Ning Yang (Part 2) [A]. Archives of the Chinese Academy of Sciences

［9］ Academic report by Chinese-American physicist Chen-Ning Yang (Part 3)[A]. Archives of the Chinese Academy of Sciences

[10] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 29 [A]. Archives of the Chinese Academy of Sciences

[11] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 12 [A]. Archives of the Chinese Academy of Sciences

[12] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 6 [A]. Archives of the Chinese Academy of Sciences

[13] Briefing on the reception of Chinese-American scientist Yang Zhenning No. 23 [A]. Archives of the Chinese Academy of Sciences

[14] Zhu Kezhen. The Complete Works of Zhu Kezhen, Volume 20[M]. Shanghai: Shanghai Science and Technology Education Press, 2011: 445.

[15] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 17 [A]. Archives of the Chinese Academy of Sciences

［16］ YIN Heping, LI Weimin. Han Chunyang Zao Painting Biography[M]. Beijing: Machinery Industry Press, 2018.

[17] Briefing on the reception of Chinese-American scientist Yang Zhenning No. 24 [A]. Archives of the Chinese Academy of Sciences

［18］ Yang Zhenning. Deng Jiaxian[J]. Twenty-first Century, 1993(17): 56-62.

[19] Yang Zhenning’s 100th birthday speech, specifically mentioning one person [DB/OL]. (2021-09-24) [2021-09-27]. https://www.tsinghua.edu.cn/info/1182/87286.htm

［20］ Physicist Reported in China[N]. The New York Times, 1971-08-08(83).

[21] Premier Zhou Enlai met and hosted a banquet for Dr. Yang Zhenning, a Chinese-American physicist, when he was in Beijing after leaving Shanghai [N]. People's Daily, 1971-08-19(01).

[22] Briefing on the reception of Chinese-American scientist Yang Zhenning No. 31 [A]. Archives of the Chinese Academy of Sciences

［23］ LUBKIN G BCN Yang discusses physics in People's Republic of China[J]. Physics Today, 1971, 24(11): 61-63.

[24] Yang Zhenning. A visit like Charles de Gaulle (1972) [M]//Forty years of reading and teaching. Hong Kong: Joint Publishing Company, 1985: 67.

[25] Briefing on the reception of Chinese-American scientist Yang Zhenning No. 32 [A]. Archives of the Chinese Academy of Sciences

[26] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 4 [A]. Archives of the Chinese Academy of Sciences

[27] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 6 [A]. Archives of the Chinese Academy of Sciences

[28] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 14 [A]. Archives of the Chinese Academy of Sciences

[29] Briefing on the reception of Chinese-American scientist Yang Zhenning, Issue 12 [A]. Archives of the Chinese Academy of Sciences

[30] Literature Research Office of the CPC Central Committee. Chronicle of Zhou Enlai (1949-1976) (Volume 2) [M]. Beijing: Central Literature Publishing House, 2007: 533.

［31］ Zhou Peiyuan. What was the intention of the “Gang of Four” in destroying basic theoretical research?[N]. People’s Daily, 1977-01-13(02).

［32］ Zhou Peiyuan. Some views on the revolution of science education in comprehensive universities[N]. Guangming Daily, 1972-10-6(01/02).

[33] Yang Zhenning. Three major contributions of Zhou Guangzhao[C]//Xu Guanhua. Comrade Guangzhao as we know him: A collection of essays on Zhou Guangzhao’s scientific thoughts and spirit. Beijing: Science Press, 2012: 3.

［34］ Chairman Mao meets with Dr. Yang Zhenning[N]. People's Daily, 1973-07-18(01).

［35］CPC Central Committee Literature Research Office. Chronicle of Mao Zedong (1949-1976)[M]. Beijing: Central Literature Publishing House, 2013: 487-488.

［36］ Integral form of gauge field[A]. Archives of the Chinese Academy of Sciences

［37］ LUBKIN G B. Physics in China[J]. Physics Today, 1972, 25(12): 23.

[38] Ren Zhigong. Memoirs of a Chinese-American Physicist[M]. Translated by Fan Dainian. Taiyuan: Shanxi University Union Press, 1992: 166-199.

［39］ Shi Yu. Huang Kexun and Yang Zhenning[J]. Nature Magazine, 2017, 39(05): 386-390.

[40] Correspondence between Qian Sanqiang and Yang Zhenning, Li Zhengdao and Zhang Shaojin during the Guangzhou Particle Physics Theory Symposium of the Chinese Academy of Sciences [A]. Archives of the Chinese Academy of Sciences

［41］ Yang Zhenning, Weng Fan. Dawn Collection (Revised Edition)[M]. Beijing: Commercial Press, 2021: 412-416.

[42] Yang Zhenning. The Responsibility of Building a Bridge of Friendship (1979) [M]//Forty Years of Reading and Teaching. Hong Kong: Joint Publishing Company, 1985: 75-76.

[43] Yang Zhenning. Dawn Collection (Revised Edition)[M]. Translated by Weng Fan. Singapore: Bafang Culture Creation Studio, 2008: 441.

[44] Yang Zhenning. Postscript to “Speech on the Great Wall” [M]//Sixty-eight Years of Journey (1945-2012). Translated by Yang Jianye and Yang Jianjun. Beijing: Sanlian Bookstore, 2014: 185.

［45］ ZHU Bangfen. Five contributions made by Mr. Yang Zhenning after his return to China[J]. Physics, 2017, 46(9): 573-581.

Further reading

Before Yang Zhenning visited mainland China in 1971, the representative achievement of Chinese particle physics research was the straton model of hadron structure. In addition, in the late 1950s, Chinese physicists also made use of the advanced equipment and international exchange environment of the Joint Institute for Nuclear Research in Dubna, Soviet Union, to make internationally influential work such as the discovery of anti-sigma negative hyperons and the proof of partial conservation laws of pseudovector currents. Interested readers can read the following two articles:

1. LIU Jinyan, WANG Fang, Alexey ZHEMCHUGOV. Chinese Scientists in Dubna (1956–1965). Chinese Annals of History of Science and Technology 5 (2021)2: 031-088.

2. Jinyan Liu, Fang Wang, Baichun Zhang. Chinese Theoretical Physicists in Dubna--A Case Study of Zhou Guangzhao. Historia Scientiarum 31 (2021) 1:3-19.

About the Author

Liu Jinyan, born in 1987, from Liaoning, is an associate researcher and is engaged in the study of the history of physics. Zhang Baichun, born in 1960, from Jilin, is a researcher and is engaged in the study of the history of science and technology, [email protected]. Wu Yueliang, born in 1962, from Jiangsu, is an academician of the Chinese Academy of Sciences and is engaged in the study of theoretical physics.

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