Epilogue of the Chinese Translation of Physical Foundations of Cosmology
This article was completed on May 30th, 2023. It was edited by the Science Press, and published on their WeChat with a weird title “I trrrrrrrrraslated Slava’s book”. In Jan 28th, 2024, I translated this article to English with the help of ChatGPT3.5. 中文版点此.
My journey in cosmology can be traced back to the spring semester of 2002 when I took Professor Yunqiang Yu’s course on Hot Big Bang Cosmology at Peking University. At that time, Peking University offered this course as a university-wide selective, attracting a diverse group of students from different departments and even humanities majors. Consequently, the course focused on popularizing the basic concepts and research methods of cosmology. Taking this course laid the foundation for my interest in cosmology. However, it wasn’t until 2006, during my postgraduate studies under the tutoring of Professor Bin Bin, that I realized cosmology could become a lifelong pursuit.
Under Professor Chen’s guidance, I started reading the review article Theory of Cosmological Perturbations by Mukhanov, Feldman, and Brandenberger. This article was detailed, not very beginner-friendly, but soon I discovered that the World Publishing Corporation reprinted version of Mukhanov’s textbook Physical Foundations of Cosmology. It presented the cosmological perturbation theory and its application to the cosmic microwave background radiation in a more accessible way for beginners. After devouring this book and a few others on cosmology around the same time, I found it to be the best.
In 2015, during my postdoctoral research at the Institute of Theoretical Physics, Chinese Academy of Sciences (ITP-CAS), I pledged to translate this book. After completing the first chapter and the last three chapters, I went to Japan for another postdoc. Subsequently, I became busy assisting Professor Misao Sasaki in establishing a new research team at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) at the University of Tokyo, and the translation project was put on hold. Part of the reason was that some people advised me against this laborious task. They argued that translated works were not recognized as academic achievements in the current evaluation system, and the English proficiency of the new generation of students was much higher, making such efforts seemingly futile.
While in Japan, I regularly attended the cosmology seminar organized by Jun’ichi Yokoyama at the Hongo Campus of the University of Tokyo. I always visited the Jimbocho Bookstore Street before the seminar. The science bookstores were filled with the latest scientific and popular science books which are promptly translated under the supervision of experts, even synchronously with the pre-order on Amazon. In such an environment, it’s no wonder scholars like Toshihide Maskawa could achieve world-class results without speaking much English. This is something we must can learn from. Somehow, I always think of Lu Xun, who went to Japan over a hundred years ago, saying, “They translated and studied new medical science no earlier than China.”……
In February 2018, I met Professor Mukhanov at Kyoto University. His Russian English was heavily accented and difficult to understand. It seemed that he would only pause for breath when his lung capacity was exhausted. During our conversation, I found out why he specifically thanked two assistants for translating Russian-style English into English in the preface. I informed him that I was translating his book and showed him the completed last three chapters. He browsed the draft again and again, and, very excitedly, showed it to Professor César Gómez sitting nearby, saying, “The Chinese trrrrrrrrranslation of my book! You see?” I asked him a few questions about the book, such as the meaning of the statement in Section 8.2.1 that small-scale perturbations would be filled by new quantum fluctuations (which is related to the later-booming swampland conjecture). Professor Mukhanov casually drew on my reprinted book to explain, dispelling my doubts. He told me that there was a serious mistake of the Tolman solution in Section 6.4.1 of the original book and advised me to check his website for the corrected version. He also mentioned that Cambridge University Press suggested adding the latest observational developments and solutions to the problems when publishing the second edition. Unfortunately, he didn’t have time to do it. In the Chinese version, I added the latest observational developments, but due to my limited skills and energy, I could only solve a few problems that I found highly relevant to the main text. This is something readers should understand.
In January 2020, I returned to my hometown, Yidu, in Hubei Province, China, amid rumors of an unknown pneumonia, which was later proved to be a catastrophe. Later, the COVID-19 pandemic broke out, and I had to work in the room of my childhood filled with old books and clutter in the great lockdown for about 4 months. At that time, I only brought an old MacBook Air 2013, which could hardly do anything, so I continued the translation. I completed the fifth and sixth chapters during this time. After joining the Institute of Theoretical Physics, Chinese Academy of Sciences at the end of the year as an associate professor, I organized a reading club on this book. On the one hand, I wanted to continue the good tradition of reading groups at the Institute of Theoretical Physics, and on the other hand, I wanted to use it as motivation to complete the translation. After this semester, I worked continuously for 20 days during the Spring Festival in 2022, finally finishing it. I reported to Professor Mukhanov by email, and he told me that he had discovered some more typos and marked them on his book. Unfortunately, since the outbreak of COVID-19, he hasn’t been to the office for more than a year, so he couldn’t show it to me. At that time, I had already compiled my own typo list, about 50 in total. After he reviewed it, he said it was helpful. He also had two suggestions. First, he recently found that the paper by Brout, Englert, Gunzig was the first to explicitly propose that exponential expansion in the early universe could solve the causality problem, preceding Alan Guth. Therefore, he suggested that I add this comment to the references in Chapter 5. Second, he mentioned that in the second edition of this book, he would include model-independent predictions of inflation, based his papers Quantum Cosmological Perturbations: Predictions and Observations (Eur.Phys.J.C 73 (2013) 2486, arXiv:1303.3925) and Inflation without Selfreproduction (Fortsch.Phys. 63 (2015) 36-41, arXiv:1409.2335). About this, I added a footnote in Section 8.6 of Chapter 8.
Although I corrected dozens of typos of the original book in the Chinese translation, for some reason, I did not obtain the source files of this book during the translation, so I had to input all the formulas myself. As a result, careful readers might notice that some formulas are typeset differently from the original book. This may lead to new typos and errors. Thanks to the efforts of colleagues and students who helped proofread, many of them have been corrected, but there may still be some overlooked. I hope enthusiastic readers could help me to correct them for the next edition (if there will be any).
In the translation process, I occasionally added some notes, including derivations of formulas, supplementary references, cross-references between sections, and so on. Originally, these were just personal notes, speculative and redundant, but Dr. Jun Qian, the editor of the Science Press, suggested keeping them, and Professor Mukhanov also encouraged me to make them public. Considering that they might be helpful for beginners, I finally kept all of them. For any scientific issues, the responsibility rests with me.
A few words about the author’s name. Long time ago, the World Publishing Corporation reprinted this book, and translated the name of the author Mukhanov as “Makehanwei” (马克翰维). This inevitably reminds us of A. Zee, who was (hilariously) translated as A Re (阿热) by mistake. Perhaps they saw that Mukhanov was the director of the Astrophysics Center at the Munich University, and pronounced it according to German. In fact, Mukhanov was born a Chuvash in Russia. However, Mukhanov is derived from Mukhan, a variant of Muhammad, and Muhammad was translated as Mahama (马哈麻) in the Yu Miliazhi Chiyu (谕米里哈只敕谕) in the fifth year of Yongle Emperor in the Ming Dynasty. So this unintentional mistake turned out to be quaint and lovely. With the opportunity of this new translation, it’s time to give him a proper Chinese name, Muhanuofu (穆哈诺夫), following the Russian pronunciation. For the reasons mentioned above, I chose Mu (穆) as the first Chinese character of Mukhanov, as it is also the first character of Muhammad (穆罕默德).
I would like to thank Professor Mukhanov for his encouragement and discussions, as well as for providing a new preface to the Chinese version. Thanks to Professor Rong-Gen Cai for his encouragement, support, and for contacting Science Press to include the book in the “21st Century Frontiers in Theoretical Physics and Interdisciplinary Disciplines Series”. Thanks to Professor Misao Sasaki for discussing issues related to cosmological perturbation theory, especially clarifying the concept of “comoving gauge.” In addition, I would like to thank colleagues who read parts of the book and provided valuable comments, including Professor Jianjun He (Section 3.5), Yibo Yang (Section 4.2), Yong Tang (Chapters 3 and 4), Chengcheng Han (Chapters 4 and 5), Yifu Cai (Chapter 7), Bin Hu (Chapter 9), Ziyun Liu (Postscript), and others. Thanks to Dr. Yili Wang, Jianing Wang, Ao Wang, and other students for reading and proofreading the entire book. Thanks to all the students who participated in the reading club at the Institute of Theoretical Physics. Many colleagues and friends have shown concern for the progress of the translation and publication of this book through various channels. I would like to express my gratitude to all of them. Finally, for the successful publication of this book, I am particularly grateful for my father’s continued tolerance and patience during my work at home.
As Professor Mukhanov mentioned in the Chinese preface, cosmology is a science that requires the use of almost all the knowledge of theoretical physics. I deeply realized this during the translation process, and I increasingly regretted my own lack of knowledge and shallow understanding. However, as Confucius said, “a gentleman should be ashamed to be unable to meet his words’’ (古者言之不出，耻躬不逮也), and I have no choice but do my best to complete this work. There must be still many flaws and errors. I hope readers will not hesitate to criticize and correct. My mailing address is the Institute of Theoretical Physics, Chinese Academy of Sciences, No.55 Zhongguancun East Road, Haidian District, Beijing. My email address is shi.pi@itp.ac.cn.
The publication of this book is supported by the National Special Support Plan for High-level Talents Top-Notch Youth Program.
Translation complete on Feb 11th, 2022
Proofreading complete on Aug 12th, 2023