It is my absolute pleasure to welcome you to the last of this year's Panitzi Lectures. And the series, as you know, is called Spreading Culture Throughout the Land, Woodblock Publishing and Chinese Book Culture in the Early Modern Era. And we are delighted once again to have with us our Panitzi Lecturer, 2021 Professor Cynthia Brokor from Brown University, where she's Professor of History and East Asian Studies and the Chen Professor of Chinese Studies. Now over the last, getting on for nearly four decades now, the Panitzi Lecture series has become really one of the great annual traditions here at the library. And each year it gives us the chance to collectively dive deep into some aspect of global history, the global history of the book in all its myriad forms. And this year already we have had, I'm delighted to say, two fascinating and illuminating lectures and tonight's promises to be equally so. It is called Empire of Texts, the Expansion of Woodblock Publishing and the Rise of the Common Reader. And my duty is simply to do a little bit of housekeeping before we come to the lecture. First of all, to say that after Cynthia has delivered her talk, there will be time, as usual, for some questions and answers. My colleague Dr. Xerxes Mazda, Head of Collections and Curations, will be here to guide you whether you're in the room or online. And afterwards, those of you who are in the building are able to very warmly invited to stay for a drinks reception after the talk. The fact that we are able to broadcast is down to the wonderful generosity of our sponsors, Jonathan A. Hill Bookseller, thank you very much. I think live streaming really transforms the impact of the Panitzi series. And if you are watching tonight, not from the theatre, but in your sitting room or your office or wherever you may be, and you do, for instance, wants to join in the Q&A, please do look for the question box below the video screen and you'll also find their social media links. And if you look above, you'll find a link to the British Library Bookshop for other information or even, if you wish, to make a donation to support the work we do here at the library. Thank you for joining us tonight. And it is now my absolute pleasure to welcome to the stage to deliver the last of the Panitzi Lectures 2021 Professor Cynthia Brokaw. Cynthia. Thank you very much. Okay, in this last lecture, I want eventually to continue to trace and elaborate on a trend that I introduced in the last lecture on late Ming book culture, the expansion of woodlock publishing and the resulting spread of texts to regions of China and levels of the population that had not previously had much access to printed books. A word, however, before getting to that topic, on the new setting for this lecture, on what is distinctive and interesting about high-end elite book culture in the second half of the early modern period and actually the early decades of the modern period. The founding of the Qing Dynasty in 1644 ushered in a book culture very different from that of the late Ming, sober and earnestly orthodox, and, if truth be told, somewhat dull when compared to the freewheeling, irreverent, and aesthetically lush book culture of the previous dynasty. There is an overall decline in the quality of printing as well. Bibliophiles find Qing printed books, even scholarly works that are scrupulously collated and edited, overall less well-cut and printed than those of the late Ming, and certainly than those of the Song Dynasty. To be sure, fine works were still produced during this last imperial dynasty, but very generally speaking, the Qing is associated with a decline in the quality of both illustration and print, pretty much at all levels of the publishing industry. The Qing was a conquest dynasty during the two and a half centuries of its duration. China was ruled by Manchus, a semi-nomadic people from the far northeastern part of East Asia, here the northern Manchurian plain, who had seized the capital of Beijing in 1644, and then launched an often brutal campaign of conquest through the central plain and down through the Lower Yangs, a Delta or Jiangnan area that we talked about last time. And that was the heart of late Ming book culture. Now in the wake of 1644, the Chinese elite humiliated by the victory of the Manchu barbarians, whose martial skill and limited literary culture were in their minds the very antithesis of the civil values and the rich written tradition of China, searched for reasons for the catastrophic overthrow of Chinese rule. They found at least some reasons in the morally lax, pleasure-loving culture of the late Ming, and what they saw as an abnegation of political and social responsibility on the part of late Ming scholars and literati, the very men whose duty it was to rule wisely. They turned to searching examination of the classics and other ancient texts in the hopes of reviving the sagely rituals and institutions that would right the great wrong of the Manchu conquest and restore Chinese rule. The great scholarly movement of the Haiqing, that is the 18th century, the evidential research movement, was devoted to close and exacting philological analysis of the classics in support of an effort to strip away all the obfuscating commentary that had grown up around these texts over the centuries so that their true meaning could be revealed and China could be restored to that perfect order that had existed under the rule of the ancient sages. Not surprisingly, this shift in scholarly interest reshaped elite book culture. Private or literati publishers garnered prestige now, not through the production of beautifully illustrated dramas and calligraphy and painting albums, as in the late Ming, but in large collectainia, or zongshu, which reproduced ancient texts and expertly collated and edited editions. Zongshu, which literally means thicket books, collected and reprinted complete works, usually linked by genre, contents, or period of authorship, under one general title. The goal was to ensure the preservation and wider circulation of excellent or rare editions of works useful to scholarship. For example, the book collector, Bao Tingbo, brought together a total of 207 ancient texts that he believed expressed and supported the study of the finest Confucian ideas and values and published them together as the collectainia of the studio of insufficient knowledge between 1772 and 1823. Here is the cover page of one part of this large work, and here is one of the ancient texts. It included biographies of exemplary women dating from the first century BCE. Bao Tingbo was the heir to a huijiu commercial fortune, and he is a good example of the kind of collaboration between wealthy merchants and learned scholars that fueled the evidential research movement in the Jiangnan area in the Qing. Interestingly, the new Manchu rulers of China were, perhaps to a somewhat surprising degree, supportive of the efforts of the educated elites in both their scholarship and publishing activities to promote a reevaluation of ancient institutions and rituals and a return to orthodox Confucian moral practice. Very aware that they were viewed with hostility and viewed as, again, barbarians by the Chinese elite, they trumpeted their devotion to Confucian values from the capital Beijing. They became, in some ways, more Confucian than the Chinese. And in the realm of publishing, they sponsored projects designed to support research on the Chinese classical tradition, and I would argue to bring home to their subjects their own mastery and ownership of that tradition. The Qing, indeed, is a period when government publishing flourished. The Imperial Printing Office at the Hall of Marshall Valor, which is in the Forbidden City in the residence of the emperor himself, employed a staff of 100 workers and produced over 500 so-called palace editions, fine works like this imperially compiled analysis of the classic of changes. This collects commentaries on the Confucian classic, the classic of changes. Again, that becomes a very widely read scholarly edition on this very important classic. It also produced works like this illustration of imperial ritual paraphernalia. This is the beautifully cut preface to that work, and here is an illustration of one ritual object. This is actually an astronomical instrument, again, at the Qing court. And this is actually an example of a rather nice illustration from the Qing. Again, undermining the general reputation the dynasty has to be a time of decline in printing quality. The Manchu emperors also commanded their bond servants to contribute to their project of celebrating and claiming ownership of Chinese culture. In 19, I'm sorry, in 1705, the Kangxi emperor, the second emperor of the Qing, had his wealthy and powerful bond servant at that point stationed in the Jiangnan city of Yangzhou, published the complete Poems of the Tong, a tribute to the golden age of Chinese poetry. This work actually comes out in 1707. This, again, is the preface of the text. The main text then opens appropriately with imperial poetry, the work of the Emperor Taizong, the second ruler of the Tang dynasty. Now, the works I've just shown you were printed by woodblock, but the Qing government also invested heavily in different technologies of textual reproduction. It supported several large-scale movable type printing projects. The imperially authorized comprehensive corpus of illustrations in books from ancient times to the present is a work of 10,000 chapters in over 5,000 fascicles and was printed from a font of between 230,000 and 250,000 bronze types and then also woodblocks for the illustrations. But the government printing office also used wooden movable type. Again, this is a work of metal movable type. In 1773, the Qianlong emperor ordered the cutting of a font of 253,000 movable wooden types. When a year later the font was completed, it was used to print a collectinia of rare books. The official in charge of this operation, actually a Korean whose Chinese name was Jinjian, then produced an illustrated manual program for printing with movable types at the Imperial Printing Office, which described with illustrations the making of the types and the printing process. And I'm showing you here two illustrations from this work. This is the first illustration which shows the actual making of the types. You see here this man in the center with a saw is sawing off the wood for the types and you see down here in the right-hand corner the man is finishing the individual types in this basket. I don't think you can see it too clearly, but this contains the cut-up types ready then to be carved with characters. Oh, and here is just a... Oops, sorry. This is the last illustration which shows the actual type setting. You see the workers here in the back of the drawers getting the various types, and here in the foreground setting them in the matrices. And here is just a close-up of the foreground with the workers filling the matrices with type. But by far the most massive publication project of the Qing court was actually a manuscript publication. The Qianlong Emperor in 1772 ordered his officials to scour the empire for the best editions of the greatest works of the Chinese tradition. These works were brought to the capital where they were reviewed and collated by a staff of 361 scholars and then recopied by an army of 3,826 scribes to become the complete collection of the four treasuries. And the four treasuries here refers to the four major bibliographical categories, the classics, the histories, the so-called masters, which basically refers to non-classical philosophers and other writings like medical writings, and then finally Belletra. The complete collection reproduced over 3,500 works in over 36,000 fascicles. Here is just one page from this massive collection. And again, this is a manuscript publication. It was not printed at the time that it was produced, although it has been thereafter put into print. And here is just another page from this collection. You note here on the left-hand side, this lists the official who was in charge of the collation and the proofreading of the text and actually the name of the scribe who wrote this particular work. Unfortunately, a byproduct of this massive project was one of the most vicious campaigns of post-publication censorship in Chinese history for in the process of collecting the editions to be included in the complete collection. The emperor also had his officials search out any works deemed subversive of Manchu rule and severely punish their authors, publishers, and owners, and sometimes all their family members as well. Now these projects, I think, are best thought of not as much as earnest efforts on the part of the Qing court to disseminate knowledge as efforts to make clear to themselves and to their Chinese subjects their devotion to and mastery of the Chinese tradition. None of these works, initially at least, were published in any quantity. Only 64 copies of the comprehensive corpus of illustrations in books were printed. Only 300 copies of the collectinia of rare texts and only seven copies of the complete collection of the four treasuries. So it's difficult to read them as anything other than grandiose assertions of Manchu imperial authority over Chinese culture. But it wasn't just Chinese culture that the Manchu's claimed to control. The Qing, unlike the Ming, was an empire that embraced not just China proper, the major area of Chinese settlement. You see here the area that is clearly most densely populated is what I would call China proper here. But also several other territories, obviously, Manchuria, the homeland of the Manchu's, but also Mongolia, what is now Xinjiang, and Tibet. The Manchu emperors thought of themselves as rulers of a universal empire that incorporated many different East and Central Asian peoples and indicated this status in the languages of imperial print. And of course they needed texts that would aid in translation among the many languages of their empire. To this end, the state commissioned works like this imperialy published textual mirror of the Qing in four scripts which consists of lists of vocabulary words ranked vertically in order from Manchu at the top, Tibetan, Mongolian, and then finally Chinese at the bottom, and then arranged in topical categories. The imperial government, however, was not the only publisher of multilingual texts. Commercial publishers produced textbooks of Manchu for the use of Chinese who wished or needed to learn the language of their rulers like this Manchu for beginners. The first line here on this page of the text tells you how to at least write, if not say, where are you from in Manchu. And even the daily use and cyclopedias of the Qing dynasty, the Qing versions of the Wanbao Transhu that we looked at last time often included chapters on Manchu, on the language of the Qing. Clearly the Manchu conquest and the expansion of the Qing to include not only China proper but significant portions of northeast and central Asia reshaped Chinese book culture, particularly at the highest levels of the publishing hierarchy. It inspired new directions and scholarship among literati eager to solve the problem of foreign conquest. The evidential research movement initiated to recover the authentic meaning of the classics. The court's sponsorship of large publishing projects helped to reorient the geography of publishing. Beijing, the imperial capital, not the cities of Jiangnan became the new scholarly book center of the empire. And the city's huge book emporium, Liu Li Chang, attracted booksellers, bibliophiles, book collectors and scholars from all over China proper. Jiangnan remained important to be sure. Its book collections supported and its wealthy merchants often funded the work of the evidential research scholars. But now in the Qing, Jiangnan had to share some of its glory with the imperial capital. And as China became now only one, albeit the most important of many languages of the empire, Chinese book culture was just one part of a very expansive Qing book culture. But to my mind, the most interesting and socially and culturally and geographically important trend in Qing era Chinese publishing unfolded at the opposite end of the publishing hierarchy in neither Jiangnan nor Beijing, but in the hardscrabble block cutting and publishing sites that began to emerge in rural hinterland regions and in the interior in the early Qing. These backwater commercial publishing industries reflected the expansion of the market in printed texts that we observed already in the late Ming in the efforts of the Zhengyang publishers to produce texts that might appeal to ordinary people of modest purchasing power. My argument is that this trend toward the popularization of print accelerated in the early Qing from the late 17th lasting through the 19th century promoting the growth of the population of common readers who now for the first time in Chinese printing history had to a certain core of universally popular texts that provided the foundation for a deeper level of cultural integration and their participation admittedly in a somewhat limited fashion in a book culture shared with the elite. The heroes of my story if it has heroes are the commercial publishers of Zhengyang in the late Ming and their successors in the Qing. What is distinctive about the trend in the Qing and what I want really to address here is the greater geographical expansion of commercial block printing and the intensified social penetration of texts to levels of the population again up to this point pretty much excluded from the book market. The publishing boom of the late Ming is at least on the production side pretty much centered in a handful of dominant sites and this area, this Jiangnan area that we talked about last time the cities of Nanjing, Hangzhou and for some reason Suzhou is not on this map but it's also an important Jiangnan publishing center and of course Zhengyang in northern Fujian. But by the 18th century at the latest commercial publishing sites had popped up in many more places throughout China proper and at almost all different levels of the settlement from peasant villages to market towns to provincial capitals as well as major metropolitan centers like Beijing. Facilitated by the simplicity portability and flexibility of wood block printing technology it was also driven by demographic and social changes distinctive to the Qing. First the very considerable population growth of the 18th century by one estimate the population grew from roughly 56 million to 400 million between 1700 and 1830 obviously this increased the demand for tax as the population grew peasants crowded off their land and then merchants seeking new business opportunities began to migrate to frontier areas or regions that had been depopulated as a result of the multiple peasant rebellions of the 17th century and of course devastation wrought by the Manchu conquest. The movement of the population served both to diffuse demand and aid the transmission of the skills and technology of wood block printing to areas previously only lightly served by print. I have done field work in several different backwater publishing or wood block cutting sites newly founded in the Qing but here will provide a brief case study of just one, the site that stands at almost the very bottom of the publishing hierarchy and thus most effectively illustrates the growing power of popular print in the Qing. This is Sibal, a cluster of villages in the mountains of western Fujian here's a map of Fujian and Sibal is so insignificant it doesn't appear on this map but it's located roughly around here Changting is actually the county seat for Sibal. This is distant from any cultural or economic center. Two single surname villages within the Sibal basin within the Sibal area were the major sites of publishing. Wuge was home of the Zou publishers the Zou lineage publishers and Ma Wu home of the Ma. So in Ma publishing houses were first established in these villages in the 1660s. The industry persisted for two and a half centuries actually over two and a half centuries. The last Sibal publishing house stopped printing only in 1946 and the last bookstore closed in 1956. Here I hope to introduce not only the operations and products of this low-level popular publishing site but also to introduce some of the sources that I have used for the study of Chinese book history. Now, publishing began in the Sibal area as a subsidiary handicraft that is as a means of supplementing an inadequate income from agriculture in a remote and poor area the fact that Western Fujian was home to a flourishing paper industry and produced all the other natural resources hardwoods for wood blocks, pine for ink necessary to publishing helped decide the choice of publishing in particular as a subsidiary industry. The technology of wood block printing was introduced to Sibal in the mid-17th century by men of the Zou and Ma lineages who returned home after working as block cutters in neighboring Guangdong province. The first shop was established in 1663 and by the end of the 17th century there were as many as 17 other print shops in Sibal. They were devoted initially to the publication of school texts, literacy primers and student-friendly versions of the classics. These businesses were hard-scrabble operations, nothing like elite publishing houses of Jiangnan or even those of the Zhenyang commercial publishers of the late Ming. The detailed genealogies of the Zou and Ma lineages and these were substantial works of 45 and 36 volumes respectively provide some information on how shops were established. I'll give you just one example of an account of the founding of one print shop the One Cui Lo in 1687. Ma Quan Hong invested the inheritance that he had received from his father into printing four school book editions of the classics. He set off to sell his products in the neighboring province Guangdong leaving his son Ma Dingbang who was only 15 at the time in charge of the print shop back home in Sibal. Ma Quan Hong left just two reels of paper as capital to supply the daily needs of the family. This paper was worth three cash. Ma Dingbang used it to print texts. When all of these had been sold he went into the mountains to buy more paper which he carried back himself and again used to print up texts. He continued this cycle and the family never suffered hunger or cold all on the strength of his two reels of paper. Later as a result of his labors his younger brother was able to marry thus those two reels of paper were made into ten million. Ma Quan Hong distant from home could begin to feel no anxiety about his family. And the enterprising Ma Dingbang went on to become one of Sibal's most prosperous publishers. Now like many other handicraft industries in South China the Sibal publishing book-selling concerns were organized as household businesses within the corporate lineages. These households usually included families of different sizes and configurations. Some were small nuclear families like that of Ma Quan Hong but some might be extended families of up to 80 or even 100 people providing ample workers for the larger print shops. The household patriarch was usually the manager with his brothers, sons and nephews working as block cutters, printers and booksellers. Women and children within the household also helped out performing the low skill tasks of printing and binding. Book production took place within the household in small stall like printing rooms flanking a courtyard which contained a tub of ink and here you see the doorways very dark again there are more stalls than rooms where the printing was done and here is a picture of one of these tubs that was used to store the ink in the central courtyard. And here just piles of wood blocks now of course useless but still preserved in Sibal and I have to point out stored incorrectly this is not the way you're supposed to keep them but as they are useless it probably doesn't make too much difference now. The main advantage of household centered production was that it kept costs down only rarely did the publishers have to hire cutters or printers outside their own households. This was essential as the Sibal publishers did not have much capital to invest in their businesses. Now in this publishing culture wood blocks were inheritable property almost as valuable as land. Property division documents recorded the divvying up of wood blocks among a publisher's sons. Here is a page from one such document dated 1839 that lists a total of 107 wood block titles and their division among the six sons of the publisher Ma Cui Zhong. Five new publishing houses were formed from this division this page again it's a much longer document but this page lists the 19 titles given to one of the heirs and includes works editions of the four books and other classics several novels and several medical texts. As you can imagine the proliferation of print shops that might result from this partable inheritance system had the potential to create considerable tension among competing brother and nephew shops. The Zhou and Ma publishers thus agreed on certain customary regulations. When a shop wanted to publish a new work it was to announce its intention by posting a notice of the title on its print shop gate at the new year and then no other shop could publish that title. If a shop rented wood blocks from another shop it had to preserve the original shop's name on the blocks only if the purchased could the shop's name be changed to that of the new owner. Finally, and this was very fortunate for the success of the smaller print shops some texts, some primers and some textbooks of the examination system for example were so universally in demand that the rule was that anybody could print them. Now what kinds of texts did this about publishers produce? What contributions if any were they making to Chinese book culture? Giving you now a very cursory overview of their publication lists in these three categories. First to talk about their educational texts. As we've seen these were the real staples of the Subao trade so popular that even just a few editions of the four books and the four books were the basic texts not only of the examination system but of schooling generally of education in general and reading primers could support a print shop. Over time the publishers added all sorts of examination study aids as well dictionaries, collections of model examination essays, encyclopedias, outline histories of China etc. I show here just a few examples of the most popular sort of educational texts. We'll begin with a reading primer, the three character classic probably the most commonly used beginning reader in late Imperial China. The text here is divided into three character rhyming phrases that introduce the vocabulary and introduce vocabulary and basic confusion values and beliefs. The very crude picture that you see at the top depicts a student standing before his teacher probably backing the book. This second text is a collection of primers and other basic educational works. The lower register here as the title informs us reproduces four popular graduated reading primers with commentary so that on the bottom register here you see the three character classic with rather extensive interlinear commentary. But then the top register contains a series of other works for beginning students here instructions on how to practice calligraphy and you see the hand here is showing you how you're supposed to hold the brush and then these samples of calligraphy and I should say this is terrible calligraphy, this is very poor calligraphy and then what follows is a very crude version of the 24 exemplars of filial piety a series of stories of extreme filial piety was used to teach that value to children. Another text this is a beginning poetry reader obviously again another crude and simple production rather poorly printed despite the fact that its title attributes the commentary to a very distinguished literatus. And now finally and then we're moving up the educational ladder here is an edition of the four books titled the collation of the full porport and explication of the subtleties of the four books with added commentary. The basic text is in this case the analytics of Confucius is on the bottom register and you see the large type is the classic or I'm sorry the large characters is the classic and the orthodox commentary to this text is the smaller interlinear character characters. The middle register offers a painstaking vernacular explanation of the meaning of the classic and the top register explains place and proper names and historical references. This work is clearly designed as a guide for examination study the cramped page and flattened characters make it an unpleasant read it's a kind of cram book on the analytics most likely designed either for an ambitious but poor student or for a teacher unsure of his own learning who has to explain the text to a student. Now not all of Subao's educational texts were oriented toward examination study here is a glossary everyone every day an edition published in 1922 that instead of introducing the beginning reader to the basic ideas and values of Confucianism as a three character classic does teaches the names of things the provinces of China animals and insects agricultural products and tools etc complete with crude but I think rather engaging illustrations this other work teaches the art of calculation that is how to use the abacus and seems to be targeting aspiring shopkeepers and merchants. So too is this work writing letters distinguishing characters a two books in one work that is designed in part on the upper register to help students learn to distinguish easily confused characters its preface contains an entertaining and I think compelling advertisement for the work it opens with a testimonial from an unidentified customer who explains that his father had ordered him to abandon his studies at the age of 18 in order quote to travel to distant places as a merchant now as an adult he bitterly regrets the resulting deficiencies in his education whenever I have to write anything I cannot distinguish clearly the forms of the different characters I scratch my head bitterly wasting much time and energy trying to think of the right character returning home to visit his family he is shocked to see that his own son who has been studying for five years has the same problem he cannot distinguish between or which means register or count book and boy which means thin or between way, slight and Jung to testify or to prove a copy of writing letters distinguishing characters and after a mere month of study is able to pass an extensive test of his ability to read accurately that only one month of work would be enough to supplement five years of study this is indeed extraordinary marvels the proud father then goes on to praise the clarity and convenience of this work the text in the bottom register again this is two books in one makes the target audience crystal clear it opens with a list of ten important principles for embarking on a profession knowing how to read knowing how to use the apicus and knowing how to distinguish between grades of silver are the most important skills if as a merchant you have these skills you will do well if you don't you will do poorly what follows then are model forms for business letters the popularity of this text of course speaks both to the expansion of the writing audience and to the larger acceptance of commerce is a respectable profession in late imperial China such works would not have been produced by commercial publishers like the Zhou and Ma had there not been a lively market for them now educational text dominated Sabao's book book list throughout its publishing history but a second category of imprints practical how to manuals designed to occupy a large share of their output these were books that were designed to be consulted as references rather than to be read through and this category includes guides to a wide variety of practical problems of daily life household encyclopedias and letter writing handbooks manuals describing the rituals of family life and the rules of polite social intercourse prescribed popular behavior and etiquette often in quite minute detail here for example is a page from the collected essentials of family rituals and model forms which provides a chart helpful in distinguishing the different degrees of mourning a reader would find his or her place on this chart organized by degree of relationship to the deceased and read what kind of mourning rituals he or she was supposed to perform this work also includes detailed instructions on terms of address I counted 158 different terms of address and self reference listed for the 42 different relationships one might have with members of one's mother's lineage again quite a bit of detail here and then it also included model invitation and letter forms for a variety of different situations and correspondence husbands writing to wives fathers to sons friends writing to friends to ask for a loan and most helpfully forms for friends who write to friends refusing to give them loans within this category of practical how to text I would also place medical and pharmaceutical manuals for do it yourself diagnosis and cure or for use by village physicians they include for example collections of rhyming prescriptions for easy memorization guides to the symptoms of various diseases there are two pages from a book that tells you basically what it is you have these two illustrations on the right the man has something wrong with his head and on the left the woman has something wrong with her tooth and then here is again a section on a baby boy or here is a page from a popular veterinary manual cures for water buffaloes by Yuan and Hung illustrating on the top register these poor diseased water buffalo writhing in agony with prescriptions in this particular copy virtually illegible for their cure below now like all texts in this how to category and like the we looked at last time these works advertise their applicability to everyone everywhere yet in rhetoric that reveals they were intended really for a rural readership of modest means for example here is an excerpt from the preface to the new collection of efficacious prescriptions there is no one who does not get sick but physicians at times are hard to get medicine at times is too expensive the poor will often be wringing their hands in anxiety over these difficulties in order to ensure the greatest convenience every household should have a copy of this text it supplies a prescription for every sickness and a medicine for every prescription moreover these prescriptions need not cost even one cash and yet are miraculously efficacious even though you live in an isolated rural area one that rarely sees a boat or horse you will still be able to find the necessary medicine now within this category of how to texts there is also a group of texts that I would call how to guides to good fortune this group includes Giamansi manuals that is works that explain how to cite the graves of deceased family members in order to bring good fortune to their descendants and the illustrations at the top of this text are pictures of grave sightings it also includes illustrated guides to physiognomy, the casting of horoscopes and the drawing of charms, morality books and almanacs that advertise a kind of good fortune through careful scheduling the record of the jade casket for example is a very popular almanac that includes a calendar of lucky and unlucky days so that the reader knows not only good days for major events like marriages and funerals but also for mundane activities like washing one's hair this text as you can see also provides pictures of a large array of spirits with brief explanations of how each might be useful to a supplement and what the most efficacious time and form of worship would be for each now the final category of text consists largely of fiction that Zhou and Ma produced all the famous vernacular novels of the early modern period, romance of the three kingdoms, bandits of the marsh Journey to the West, The Plum and the Golden Days and Dream of the Red Chamber but by far the most popular texts in this category were highly fictionalized historical novels and martial arts romances, stories of famous historical heroes like UFA and Judge Bao and their miraculous at times supernatural feats of military daring and then of course also very popular were scholar beauty love stories very popular too were song books cheap pamphlet like texts that were used as prompt books and local performances of such famous narrative songs as the tragic love story of Liang Shan Bo and Zhu Yingtai very few works of fiction survive from Sibao I can show you only this very crudely illustrated and badly printed sheet from Liang Shan Bo and Zhu Yingtai now what I've shown you here is a very very small sampling of the titles that the Sibao publishers produced in their mountain backwater how did these titles fit into the larger Chinese book culture of the day well the overwhelming majority of the texts that Zhou and Ma published were universally popular works texts that would have been demand throughout China proper the Zhou and Ma publishers were choosing to produce the perennial best sellers of Chinese book culture works they were confident that they could sell anywhere any time to risk any kind of adventuresome investment in untried titles would have been to invite financial ruin the Zhou boast in their genealogy spreading culture throughout the land they were in fact doing just that but the culture they were spreading was very much the culture of tried and trues, school texts, practical how to manuals and entertainment literature now I don't mean to suggest that they were unresponsive to new works and new trends they clearly kept their eyes on changes in the examination system requirements issued from Beijing and adjusted their output accordingly adding new works with actually quite impressive speed and in their own modest way they added to Chinese book culture the publisher Zhou and Ma pictured here rather like the Zhen yang publisher Yu Xiang Dou in the guise of a literate sitting in his study you see the book stacked to his his right wrote a frequently reprinted guide to the classics and edited and expanded a textbook of illusions titled a treasury of stories for children this is the sobao edition of the work it is actually still reprinted today here is a modern edition of this work and his sons compiled one of the most popular daily use encyclopedias of the Qing the broad sack of social tips but even in these works the culture they were spreading was mainstream and thanks in part to their efforts increasingly familiar to common readers throughout China proper of course and I think I need not belabor this point it's obvious from my slides the works they published were for the most part poorly produced small in size printed on bamboo paper from blocks that were crammed with crudely cut characters they were often full of mistakes this is actually a page from the daily use encyclopedia I just showed you they fully support the consensus among book scholars that the Qing period marks a decline in printing and editing quality but the benefit here of course was that these works because production costs were so low could be sold at low prices a tattered print shop inventory it has barely survived from the 19th century list prices for Sibao books as low as five li let's say that's a few pens and wholesale prices for versions of the three character classic and other primers again that's the five li just a few pens and say three fun about let's say 30 pence wholesale for an edition of 300 poems of the Tong and simply annotated editions of the classics as one informant explained to me our texts were so cheap that anyone could buy them and just as an aside here this inventory lists at the top the number of volumes that they still have in stock an abbreviated title of the work and then a price of work now this raises the question who did buy Sibao texts who were the common readers of my title and where were they at the beginning of its printing history as I've said Sibao publishers supplied texts to local schools but as the print shops proliferated and production grew booksellers sought out new markets we've seen that even as early as 1687 when Ma Chun Hong went off to sell books in Guangdong leaving his family behind Sibao publisher booksellers were striking out beyond their home as sojourning book merchants their sojourning took two different forms some were itinerant booksellers who traveled from market town to market town or school to school in an established circuit of bookselling for example one of my informants reported having worked with his father and uncle as a book peddler in the 1920s and 1930s each carrying two boxes of books here is one of these book boxes they would carry on a shoulder pole the father uncle and son traveled on a circuit of market towns and villages in Fujian timing their arrival with that of periodic market days in these towns displaying their texts in a temporary market stall spreading them out on a bamboo mat on the ground as this watercolor of a bookseller illustrates just as an aside here I have to say books at least when I was doing my field work in the 1990s and early 2000s were still being sold in this way in certain areas of rural China when I was living in Wuga I was delighted to see on market day an itinerant bookseller displaying on a plastic mat spread out on the ground cheap modern editions of the classic of changes horoscope manuals sensational novels and highly fictionalized biographies of Bill Gates and Marilyn Monroe so here the booksellers the Zhou and Ma booksellers were taking books deep into the countryside to villages not served by a permanent bookstore and his residents thus relied on itinerant booksellers passing through for the purchase of texts but some sojourning publisher booksellers established branch publishing enterprises distant from Sibao they would sell Sibao texts but also works of their own manufacture they might be away from home for decades managing the distant shop and often starting another family but they often return to Sibao on retirement the branch shops were usually established for urban settlement of some sort for example Boise a town in western Guangxi over 1200 kilometers distant from Sibao these branch shops also served as headquarters for new groups of itinerant booksellers the account book of an itinerant bookseller who worked in western Guangxi countryside survives from the entries we see that he was traveling from village to village here he would list the place name of the school that he was attending and then the names of his customers and then an abbreviated title of what he was selling them and what they owed him these particular customers were purchasing the treasury of stories for children a ritual manual and copies of the four books the genealogies of the Zhou and Ma lineages also recorded the establishment of some branch shops as in this entry here explaining Zhou Xihua Dao's founding of a branch bookstore in Wanzhou in the early 19th century so it's this kind of information that allows us to reconstruct Sibao booksellings roots the territory they covered was both impressively broad and impressively deep they gradually extended their markets first from Fujian province here right here Fujian westward into Zhangxi and further westward into Kunan and then north northward into Hubei and then also starting from Fujian into Guangdong province and Guangxi province ultimately they reached six of the nine provinces of south China I've been able to reconstruct their book selling sites in their own native province Fujian they were selling in all of the sites listed on that map in Guangdong which was probably their largest market and then finally in Guangxi province and you see the city where they establish a branch shop this was the one that was most distant from the homeland Sibao in this expansion the Sibao booksellers usually avoided metropolitan areas where they would likely face competition from larger publishing operations they focus their efforts rather at first on intermediate sites perfectural and county seats the sites of government schools which of course offered good markets books increasingly over the course of the 18th 19th centuries they sought out even lower level settlements market towns and peasant villages the audience they hoped to reach was composed largely of males who had received some schooling including boys and men preparing to take the examinations and Sheng Yuan that is men who had succeeded in stepping up to the lowest rung in the three levels of the examination but also merchants shopkeepers, government clerks peasant farmers of some substance hired laborers, transport workers and some women Sibao was not by any means unique among South China publishing sites either in its production of relatively inexpensive universally popular texts or in its distribution of these texts over an extensive geographical area and down to the lowest social levels of the population Foreign observers were quick to notice the widespread availability of print, you will remember the testimony cited in my first lecture of the missionary W. H. Medhurst writing about Chinese publishing in the 1830s after explaining that the cheap price of paper and labor quote enables the Chinese to furnish books to each other for next to nothing he notes the result that the Chinese are multiplied at a cheap rate to an almost indefinite extent and every peasant and peddler has the common depositories of knowledge within his reach now in these lectures I have presumptuously attempted in just three hours to introduce pre-modern Chinese book culture I could not do justice to that culture in such a short time and I assure you I am painfully aware of how official this series of sort of leaps through the history of Chinese publishing have been but I hope in these lectures I have at the very least persuaded you of the sophistication technological and aesthetic of pre-modern, particularly early modern Chinese xylographic book culture and Pache Douglas McMurtry of its historical importance in each lecture I have provided a glance at high end production in the Song on the close tie between the examination system and book production and the golden age calligraphy of the Song in the late Ming on the production of beautifully illustrated and often beautifully colored perhaps rather frivolous luxury texts and in the Qing on the role of the state and the new movement in classical scholarship and shaping the more sober book culture of that dynasty there is no question that in these lectures I have slighted high end and for that matter middle range publishing so that I would have time to treat the slice of Chinese book history and publishing culture that is my special interest popular commercial publishing the publication of text designed for the common reader not the highly literate scholar you can see particularly in this lecture where this has landed us the last half hour looking at shabby frankly ugly text crudely cut and poorly printed from warren wood blocks but attention to the expansion of print and the growth of the book market for common readers I think allows for reflection about the broader social cultural and political impact of print in a way that I think is fairly important this is about publisher booksellers and again many others like them by disseminating the universally popular text for the best sellers of Chinese book culture to a growing population of common readers in South China or acting as agents unwitting to be sure of cultural integration across both geographical and status lines Arthur Smith a British missionary remarking on what he saw as a high degree of cultural integration in late 19th century China observed the classical wisdom of the ancients is the common heritage of all the sons and daughters of Han from emperors to old women and one stratum of the society can quote them as well as another Smith is speaking here of tags from the classics but it was of course not just the classical wisdom that the Zhou and Mao were transmitting but also guides to ritual practice and etiquette, popular stories and songs that just as much as the classics contributed to the common core of cultural reference that supported some degree of cultural integration and a growing sense of Chinese cultural identity now of course there were divisions and tensions within early modern and modern Chinese book culture that worked against integration the common reader had little if any access to the highest levels of elite book culture beautifully printed luxury editions and fast-breaking works conveying the latest literary fashions or the hottest and most controversial contemporary scholarship like that of the evidential research movement were out of reach of the common reader furthermore it's clear that learning to read from the three-character classic on the right would be a very different experience from learning from the one on the left a nice edition published in Suzhou in 1778 and there were also local or regional book cultures texts in dialect produced for local consumption that would inevitably have limited circulation and reinforce regional and local differences but thanks to the efforts of commercial publishers like the Zhou and Ma an increasing number of common readers engaged for the first time in the 18th and 19th centuries in the foundational works of Chinese textual culture I'd just like to end by again thanking the Penizi Council for inviting me to present this series it's the very least been very useful to me to have to reflect on all of these problems and again thank you very much for attending. Thank you so much indeed for incredibly detailed but yet very very broad and incredibly clear and illuminating three hours I now I think we move on to the questions we have about 10 minutes those of you who are watching from online please do type in your questions I should be able to receive them here and those of you in the room just raise your hand and I'll mix the two together when you do ask a question just wait for the microphones so people who are listening online can hear OK. Hi there, that was amazing I loved every single lecture it's just been fantastic through all the lectures we've been talking about these master carvers imitating say master calligraphers in their printing and then talking about all these environments of learning I think there was some lovely quotes about how people could talk forever and all about honing the craft and then we looked at these encyclopedias that were so far removed in what they were saying about calligraphy they didn't even attempt to replicate it and I just wondered if there are any tensions between this culture of learning from masters in person and then print being more available on people learning from that Yeah I would say there certainly is a tension that I kind of briefly alluded to in my very last comments but again I'm arguing for some degree of cultural integration and some degree of communication between the different levels of the book culture but there's no question that an elite scholar who would be used to and would value books that were produced in fine calligraphy by master cutters would be contemptuous of the productions from Soval that I showed you and this tradition of cutting by masters does continue through the Qing even though there is this kind of decline in publishing quality I do think however one of the things that does change is that link between the calligraphy of the texts and the calligraphy of the great calligraphers of the Tong they all seem to be from the Tong there is one from the Yuan dynasty as well that seems to dissolve over time there seems to be less attention paid to that in the Ming and in the Qing so there's still a value placed on beautifully cut books but there's not the effort to link it to some famous calligrapher of the past does that answer your question? Thank you I've got three questions from online Laura asks two questions starts by saying thank you for yet another wonderful lecture fascinating I'd love to ask two questions about the Sebao Publications do you have information about when the inventory with prices that she showed was produced is the first one? I have only rather soft information about that and that is from a local informant who was holding on to this he said that it was an inventory from the 1880s from his own family's print shop the one high low but I have to rely on his there's no date actually on the inventory itself so I have to rely on his word for that and it's not really possible to date it from the texts that are listed because again these were texts that were published over and over again throughout the centuries thank you and then did the Sebao Publishers issue any form of printed book trade catalogs and or publishers catalog? I wish no not that I'm aware at any rate the in addition to that account book or that inventory I do have another inventory that again I can't really say it's a catalog but it's in fact more detailed than the one I showed you and in some ways a little bit more useful that lists hundreds of works the tattered one I showed you has 379 legible titles there's some titles I couldn't figure out this one would have over like 500 titles but it's not a catalog and indeed as far as I know book catalogs aren't really issued in China until the very late 19th century and then they begin to proliferate in the early 20th century but it doesn't seem to have been a very common practice to the best of my knowledge. Thank you questions in the room please oh sorry this gentleman at the front thanks thank you I wanted to ask a wonderful lecture I wanted to ask about censorship if I may first of all one thing that slightly there's two parts to it I didn't quite understand puzzled by with the the Manchu and the imperial printing effort how that therefore also I think you said increased censorship as well I didn't see how the two sort of were together and then secondly on censorship with the Sabao publishing and the extension of common printing as you said as well with greater social penetration as well as greater geographical spread was there any censorship there did it conflict with anything or were was it below the radar or is there an issue about censorship? Okay the first one the censorship basically what happens is the Qianlong Emperor the man who sponsors this huge manuscript project was very sensitive to any slights against the Manchus and again he sort of takes advantage of this project of collecting all these texts but they had collect texts from book collectors throughout the empire to publish this complete collection of the four treasuries and he has his officials at the same time that they're collecting the finest you know additions of all these various texts also investigate texts that were subversive or critical subversive of Manchu rule or critical of the Manchus in any way and it didn't take much to be taken as critical of the Manchus or subversive of Qianlong rule you also I mean people were offered rewards for reporting such texts and their owners and you can imagine what happened there you know people settling old scores thinking of ways to steal their neighbor's land you know by reporting the existence of these subversive texts and an example of how little it would take there's an incident where a merchant with scholarly interests commissions a history of the Ming dynasty the previous dynasty and he doesn't write it but the man he commissions to write it includes in that history a discussion of the emperors at the very end of the Ming who are fighting the Manchus who are resisting Manchu rule I mean this movement collapses ignominiously and all of that it's not important but the very fact that he mentions the reign dates of these men is enough the emperor in a fury has the merchant who was died by this time has his body exhumed and torn apart and scattered it was a horrible sacrilegious blasphemous thing to do to the deceased and then anybody at all involved with the project is executed their family members might be executed just this massive campaign so it didn't take very much for a book to be considered critical of Manchu rule so does that kind of answer I mean I could go on in great length but I'll stop there so that was interesting nobody seems to have paid much attention to what Sobao was publishing there were efforts to prohibit the publication of certain books I've mentioned bandits of the marsh repeatedly in these lectures that's a book that has as its heroes a group of bandits who spend most of their time attacking officials so obviously a work that could be considered subversive so it's repeatedly prohibited yet it's one of the most popular novels of the late Ming and the Qing there is a story about another commercial, popular commercial publishing site in the Qing the official had a steely erected right in front of the row of the major print shops that listed 200 titles of the works that were prohibited that they weren't supposed to publish but they published them anyway and nothing seemed to have happened to them so again it's not that there weren't efforts to censor these works and some of these efforts were successful but when it comes to these relatively below the radar radar commercial publishers they seem to have been able to get away with quite a bit thank you very much and thank you for such a graphic I'm sorry a little too much description there I think we have time for just one more question because I'm very conscious that I'm the person standing between you and the reception one last question from within the room there's a gentleman up the back with these cheap books do you have an idea as to how many households owned one or more books or what the literary rate was no I don't know how many households owned books maybe very quickly that there's an enormous regional difference probably many more people in south China owned books than in north China maybe afterwards I can go into the details there literacy rates I don't know how useful I don't think it's possible to say what the literacy rate is and I'm even skeptical of the effort to try basically because there's so many different kinds of literacy there's so many different levels of literacy coming up with one rate doesn't seem to me to be particularly helpful I will say just to give you a sort of complete answer that people have tried and the range is quite remarkable from 5% to 40% that gives you some idea of what the problems are obviously 5% would be identifying the highest literacy fully literate people whereas 40% would include people who are perhaps semi-literate or have only functional literacy but it's I suspect an unsolvable problem at least before the 20th century thank you very much indeed and for all of you who are joining us for the reception you will have a chance to carry on the discussion outside and it just remains then for me to say once again a huge thank you on behalf of everyone here who's been at the three lectures on behalf of the Penitzi Council on behalf of the several hundred people who've been watching online each of the lectures there's been an extraordinary privilege and a pleasure to spend three hours in your company in the company of your great minds and all your research so thank you very much indeed


Okay, thank you very much in the first place I would like to thank the organizers for putting together such a nice workshop and for the opportunity to give a presentation Today I will talk about the dynamical structure factor of the triangular Heisenberg model a quite old problem And this is work that you know we did in collaboration with Shang-Shun Shang He's a postdoc at the University of Tennessee Yoshitomo Kamiya who is at Rican right now, but he's moving soon to Xiaotong University in Shanghai as an assistant professor My friends and collaborators from the Institute of the Physics at the Rosario, Esteban Joldy, Adolfo Trumper, Mattia Gonzalez and Luis Manuel There is also a long list of Experimentalists that you know collaborated at different stages of these projects and actually provided the inspiration you know for what I'm going to describe in the second part of the talk and And the story really starts with this cobalt based Compound cobalt in this material is in a d7 configuration is cobalt 3 plus So we have seven electrons in the digital that means five in the t2g orbitals two in the issues So we have a spin three halves and an effective l equal to one So out of the spin orbit coupling we end up with a low-energy doublet j equal one-half separated by 250 k From the j equal three-halves doublet and then you know at an even higher energy you have the J equal five-halves so but the important thing is that this gap is two orders of magnitude bigger than the Scale of the interaction between these tablets meaning that you know one can really get rid You know of these higher energy multiplets and end up with an effective spin a half Heisenberg model and because this octahedra. I mean the octahedra that is around each cobalt are you know Have octahedral symmetry to a very good approximation you end up with a very You know to a very good approximation with an isotropic Heisenberg interaction actually DM interactions are Not allowed by symmetry in this material There is a weak easy plane an isotropy as we'll see simply because there is still some distortion and We as I will explain in a moment this is indeed a good realization of a quasi two-dimensional, you know Heisenberg model So this is the effective Hamiltonian for the lowest energy doublet you have as I said an Effective easy plane an isotropy is roughly 10% And then there is an interlayer in exchange that is of the order of 5% times the interlayer interaction So it's a nice Realization of the Heisenberg model in a triangular lattice and actually when you go and do different kind of experiments measuring essentially static properties like the magnetization versus field and Other properties that they don't have to time to summarize in this talk You get essentially the the phase diagram that was originally obtained by and Ray and And Golozov in in this seminar work in 1991 where they use basically a semi-classical approach One-hour expansion and they show that as you increase the magnetic field So at zero magnetic field you have this one known 120-degree magnetic ordering and then as you increase the magnetic field There is some Accidental degeneracy at the classical level that is removed by order by disorder by quantum fluctuations. So these 120-degree ordering basically evolves into this kind of Y-shaped type of configuration for the three sub lattices Eventually you reach Critical magnetic field where quantum fluctuations Stabilize this plateau phase where two sub lattices are up and one sub lattice is down So this this this plateau phase that was predicted in this paper is of intrinsic quantum origin and then You continue with this kind of V-shaped phase The beers in this phase diagram and this kind of w-phase if you want appears in the in this material Simply because of the interlayer interaction. So that is a consequence of the actually 3d structure of this of this model But you know as you can see The the quantum phase that is is really well described by this semi-classical approach and actually one can also Describe the NMR line shape, you know for the different phases that are appearing as a function of field So no mystery up to this point. So the surprise appeared when my colleagues, you know from Oak Ridge Went and measured the inelastic neutrons scattering spectrum of this Sorry At zero magnetic field as a function of temperature. Sorry Yes, you mean as a function of temperature as a function as a function of temperature Yes, so what is the question if there is a phase transition one of Yeah, I mean like for the for the three-dimensional You're talking about the two-dimension or the three-dimension Yeah, really, right? So so anyway So let me continue. So this is the inelastic scattering spectrum and the anomaly that you know, my colleagues notice in This spectrum was an anomalous broadening of the magnum peak of the magnet line around this point of the virion zone This is the end point. So this is a cat as a function of energy at the end point and The only thing they know this is that the width of these peaks was Significantly larger than the experimental resolution. So this was actually the motivation for trying to understand You know first the origin of this broadening if it was real And and the first thing you do is you say well, you know probably this in a semi-classical description This broadening is produced by single magnet to two magnetic case So you go include the next order correction in one over S you go beyond linear spin waves and You try to see if you can explain this broadening in that way and also the spin the bandwidth renormalization that that that is observed because you know, if you Essentially compute with the linear spin wave theory you get these white lines that you know have a bandwidth that is much bigger than than the experimental bang now As I will explain in a moment actually that doesn't work For for reasons that will become clear immediately So first of all with this kind of model You don't get spontaneous single magnet to two magnet decay because the kinematic conditions are violated And that's essentially because of the easy plane anisotropy that you have in the material that although it's small is relevant But you know what actually was more so basically what happens is you do the non-linear spin wave calculation You get I mean you know the exchange parameters here by different means, you know from thermodynamic measurements and also from the long wavelength limit of this Spinway calculation in the long wavelength limit even the linear spin wave is a good approach and you end up with With a bandwidth with a non-linear spin wave theory that is 2.4 million electron volts while the experimental bandwidth is 1.6 So here you have another anomaly, but perhaps the most interesting anomaly is what happens in the high energy part of the spectrum And this was revealed by a beautiful experiment that came afterwards in 2017 the group of professor Tanaka in Japan Where he showed that besides, you know the magnet dispersion that you have at low energies You get all these spectral weight at higher energies that is also dispersive Right so here you can see again a cat at the end point. So this is this point in the brilliant zone So here these are the two magnum peaks at low energy and here you have this broad continuum that according to This group extends up to six times the single magnum bandwidth And moreover when you go and integrate the weight under this continuum It's roughly is more than twice the weight that you have under the two magnum peaks If you go and do the non-linear spin wave calculation at the same point What you get is two very sharp magnum peaks and a very small Intensity in the continuum. So actually intensity in the continuum Turns out to be significantly smaller than the intensity that you have 1.5 times smaller that you have under the magnum peaks So the question is why first of all why this semi-classical approach? You know, it's not explained. It's not producing a large renormalization of the bandwidth that you will expect for the isotropic model and Second why is that? You know, you don't get this kind of broadening of of the magnum peaks that you will also expect for the isotropic model So first of all why in the isotropic limit you do expect some strong renormalization So the reason is that in the isotropic limit you have two types of goals the most you have one goes to mode around the K equal to zero the gamma point and and Two goals to most around plus K and minus K and these goals to most have different velocities meaning that if you start with a magnum That has higher velocity around the gamma point that can decay into two magnums at K and minus K, right? and because of that This single magnum mode enters in the two-magnum continuum You have single-magnum to two-magnum decay because of cubic processes that are allowed in this case because the ordering is non-colinear Besides, you know this broadening of the single-magnum line you get the strong renormalization of the magnum bandwidth that was noticed already in this paper and explained very beautifully in this other paper by Chitomirsky and Sasha Chernichev The problem is that as soon as you put a small anisotropy 10% right you go up out this mode Right you go from having three goals to most having one And now Kinematic conditions do not allow any more to you know for this this magnum cannot decay into two minus here because you know this This will correspond to a very high Energy final state so you cannot conserve energy and momentum Anymore so now you know the two-magnum continuum You get separated from the single-magnum dispersion and you don't have the strong renormalization that you will expect for the isotropic limit It is because of that essentially that you know you go from this picture that this what you will obtain in the isotropic limit You have one you know stable magnum mode and this one that you can see is over damped to this picture Well now you have you know two very sharp Magnum modes and now a small intensity in the continuum here you have a large intensity This again is the isotropic case. This is the real case I mean for that applies to this material where actually you have two things that are playing against this single Magnum this single magnet to magnet decay the anisotropy and actually the interlayer interaction also is important anyway, so Then the question is okay Is this an old and are these anomalies that are observed at zero magnetic field of intrinsic origin or it is disorder or phonons Or something extrinsic that is produced in this behavior So one way of answering that question is you apply magnetic field Right by applying magnetic field you make the system more classical is classical you start suppressing quantum fluctuations and then you expect that if Disorder is not present and if spin of honor interaction is weak Then at some point this Semi-classical approach should start working now in this material Ideally you would like to go to the saturation field but in this material the saturation field is 30 Tesla So you cannot do neutrons scattering in 30 Tesla But what you can do is you can reach with 10 Tesla this up-up down phase the first plateau Right that this collinear is gap So you expect that although it is stabilized by quantum fluctuations as semi-classical approach actually will work reasonably well to Describe the excitations and actually that was I mean it is tricky how to implement a semi-classical approach here Because this phase is stabilized by quantum fluctuations. So you need to Use some sort of trick that was introduced in this paper by Jason Alicia and company What you do is you choose the magnetic field For which the classical phase iron will give you this up up down ordering is one precise value of the magnetic field You do the non-linear spin wave Approximation on top of that point and then you introduce as a perturbation the deviation of the field from that point Right, you will get the gap dispersion. So it will be robust Until you know at some point, you know for some critical value of the field You the gap will close and you will have a transition into this phase or this phase Depending on whether you're increasing or decreasing the field relative to that point One important thing is that Because the interlayer interaction is anti-phoromagnetic the minority spin, right alternates You know from one sub lattice to another sub lattice when you go from one layer to another meaning that you have a doubling of the unit cell along the C-direction So when you go and compare Right the results of this non-linear spin wave Approximation with experiment now you get the beautiful agreement Right the reason why you see, you know, two magnetic lines that are separated by a small energy is because of this doubling of the unit cell along the C-direction and The splitting is small because the interlayer coupling is only 5% of the interlayer good, so Moreover, if you now Change the magnetic field and and look at the low energy branches What you do? I mean what you get is a confirmation of what was predicted in this paper by Jason Alicia and company which is that the lowest energy branches I mean different low energy branches get gapless So if you increase the field, you know, this low energy branch becomes gapless and that signals the transition into this kind of B-shaped face if you lower the field This other branch becomes gapless and that signals the transition into this kind of why Why like face right and you can see that agreement is remarkably good over the whole Field range that covers this this plateau. So bottom line Semi-classical theory works really well. You get essentially the same model the parameters are fixed, right? So we have a situation where Semi-classical theory works really well in the plateau phase 10.5 Tesla But it fails in different aspects at zero magnetic field So that at least Indicates that these deviations that observe at zero field have an intrinsic quantum origin and that sets a challenge, right for you know, how do we describe them? the spectrum of this Triangular lattice system at zero magnetic field and this is the moment where you start remembering that you know actually many years ago Phil Anderson proposed this model as you know potential model for realizing the RBB spin liquid later on Simulations numerical work show that actually the system does order magnetically Although as I will discuss in a moment the reduction of the order of moment is more than 50 percent, right? so So basically what may be happening in the system is that although it orders magnetically it is not too far from Let's say the quantum melting point that will indicate a transition into a spin liquid phase And actually there are DMRG calculations by Steve White and Sasha Cherneshev recently that showed that if you put the second Neighbor interaction that is 5% of the first neighbor interaction That's enough to melt this 120 degree ordering into a spin liquid. That is the MRG results So indeed it is true that we are close to one of these points And then the question is okay if we were far away deep inside the semi-classical regime, you know It's natural to use a gas of non-interacting magnets as your starting point Essentially that is largest expansion and then try to understand the excitations, you know in terms of semi-classical theory, but if if it turns out that you are close to this point Then you know probably it is not a good idea to start with a gas of non-interacting magnets Maybe it is better to start with a gas of non-interacting spinons and then recover the magnets through a Higgs condensation basically of this spinon field and Essentially the magnets will become collecting modes in this gas of spinons that interact via gauge fluctuations So those are nice words. The question is how do you implement that? And you know the natural way of implementing that is through a large N expansion, right? So you can now choose to represent your spins in terms of bilinear forms of this So-called Schwinger boson operators and in order to fix the representation of your spin field You need to impose a constraint that is the total number of bosons here bosons have two flavors up and down because we are working with EC2 and Basically the number of these bosons in each side, you know determines the representation so if we work if we focus on spin what how we have one boson per side and And normally when you implement I mean the original formulation of a row as an hour back If you do simply saddle point or or mean field one of the nice things about this approach is that the the fields that you condense are Invariant under the symmetry group of the Hamiltonian in other words They are singlets both of them are singlets and the rotations and loud and like the usual mean field theory where you condense things that break the symmetry and So basically the order in here in this approach occurs be a spontaneous symmetry breaking be a spontaneous Condensation of these bosons. You are not breaking the symmetry by So and it turns out that you know if you had a bipartite lattice with anti-ferromagnetic Ordering this will be the right operator to condense if you had ferromagnetic ordering on a bipartite system This will be the operator that you condense but you know if you have a hundred and twenty degree ordering You have both ferro and anti-ferro components So it's better to keep both and there are some deeper reasons for keeping both that actually are describing this paper of Rebecca And peers because you know if you want to do a large in expansion in a non-bipartite system You need to work with the SPN group and this becomes the natural the composition So if you want to go beyond the saddle point Approximation because I mentioned that they want to include the interaction between spinons It is better to go directly to Path integral formulation of the problem. So you write your Lagrangian now There is the topological term in terms of the finger bosons plus the Hamiltonian you add the sources that you need to compute Correlation functions and something that is critical in this calculation is you add a small symmetry breaking field Because these bosons when they condense they can condense in a singlet state They can condense in the state that you know actually breaks the symmetry and gives you the hundred and twenty degree ordering and to get that condensate the one that you know corresponds to 120 degree ordering you need to do what is Describing the books essentially put a small symmetry breaking field You first take the thermodynamic limit and then you send that magnetic field to zero Right in that way you make sure that you are condensing the bosons in the states that you know gives you the hundred and twenty degree Ordering and then you will get you know different You know transverse and longitudinal modes and so on and so forth so The rest of the story is basically straightforward You you now introduce a Havars-Trotonovich The composition using these fields A and B that I introduced before you integrate out the bosons And you end up with an action that is a function of your Havars-Trotonovich fields The phases of these Havars-Trotonovich fields and the chemical potential sorry here You know this basically chemical potential is introduced here to enforce the constraint of one particle per side Those are basically the gauge fields of your theory that are coupled to this pin-on field and In order to develop some diagrammatic expansion of this problem Your basic elements are the spinon propagator at the saddle point level The RPA propagator that is essentially the inverse of the fluctuation matrix that you get If you do a Gaussian expansion around the saddle point in these Havars-Trotonovich fields And then you have external vertices associated with these sources J that you need for computing, you know correlation functions and you have internal vertices that you know give you the Interaction between this matter field the spinon field with with the gauge field So At the saddle point level, we know that we are going to get a result that is qualitatively wrong Right because at the saddle point level our spinons are non-interacting. They are free So basically if we compute them at the dynamical susceptibility What you will get is you know, we insert a spin excitation that spin excitation will decay into two spinons, right? The spinons will reconnect and come out Meaning that what you will get is simply a two spinon continuum, right? Branch cut singularity, no poles, no magnets And this is the reason why no one really likes to use this approach At least at the saddle point level to describe, you know, the magnetic excitation of a magnetically ordered system You need to go beyond saddle point So now if you go beyond the saddle point level You get these four diagrams to order one over n the way you compute the order of a diagram is You each wave line each RPA propagator introduces a one over n and each internal loop like this one Introduce a factor of n so you can count and see that you know here You have only one wave line one over n one wave line one over n one wave line one over n Here one wave line one internal loop Basic it's two wave line sorry and one internal loop again one over n now in the rest of the talk I will focus on this diagram and the reason is that this is the only diagram that can introduce poles in in the In in in the s of k and we are looking for magnets for poles And you can immediately see here that this RPA propagator is evaluated the same k and omega as the external line So poles of the RPA propagator will immediately become the new poles that you get in s of q and omega now that diagram Right, you know, it's interesting to to see what happens if you Compute that diagram on top of a condensate that doesn't break the symmetry, right? So if you condense your spin-ons in a singlet state This diagram contains this loop this loop is a cross susceptibility between an external line and an internal field As I explained before the external lines, of course are basically spin components, right? They transform like vectors The internal lines are these have a straight on each fields that I said the air sky scalars So if your ground state at the saddle point level is a singlet state The expectation value of this bubble will be zero right so this diagram will will cancel Now this is the reason why it is important to put this symmetry breaking field because you know Once you have a spin-on condensate in this broken symmetry state this diagram this bubble actually becomes non-zero This diagram then Becomes finite and when you go and compute so you add this correction to the saddle point Level so you get this comparison. So this is what you get at the saddle point level This is the component of the dynamical spin structure factor in the direction perpendicular to the plane of the hundred and twenty degree ordering While this is The component in the plane, right? You have the two directions are equivalent in that plane So you get here I'm plotting the average of those two components And this is the sum of of these two the sum of the three is the trace if you want of s of q and omega Now there are several disturbing things at the saddle point level So I mentioned already one the fact that you know these lines actually are not poles are branch cut singularities That you know correspond to the lower edge of this to spin-on continuum But moreover you get these porous modes, right and physical modes That you can tell that they are unphysical because if instead of computing the s of q and omega you compute the density density correlations You get a maximum at these modes and you know that density should not fluctuate in this approach, right? You know the constraint is that you should have one boson per site So you know that these modes aren't physical So these are the two reasons why you know people try to stay away, right? You know from this kind of saddle points if you are describing a magnetically ordered seat The nice surprise is that as soon as you add these Gaussian fluctuations this other than first of all this spurious modes cancel exactly The second thing is that this maximum that you get at the lower edge of the two spin-on continuum right this part disappears and Moreover, you start getting your magnum dispersion, right? You're collecting modes at low energies right here. You can see it more clearly the magnum dispersion Right, so now you recover your magnum modes and you eliminate all these porous effects That you get at the saddle points and to show you in that in more detail You know here. I'm showing the saddle point result This is you know spurious mode plus the bottom of the two spin-on continuum You can see that the one over end correction cancels exactly these contributions and now The new thing is a new pick that you know is a pole now It's a magnum in s of q and omega, right? So you get the qualitative improvement when you include this correction now Although this story is all motivated by the high energy modes by the fact that you know Tanaka observed this continuum of high energy modes up to roughly six times the magnum bandwidth Sanity check of the story is to go to the long wavelength limit now and try to see if you know this reproduces what You get from spring waves that you know that it should work in the long wavelength. Yes Right, so it's it's one over end correction is this blue line, right? It's the diagram that they showed before right the wavy line You don't need to put any to put any particular value of n at this point You are summing you know contributions coming from you know diagrams that appear to different order in one over I don't need to specify n at this point, right? Well if n is equal to infinity, then you know you will get you know Basically you will end up with this but if n is equal to infinity, then you know this other point also doesn't make any sense Basically here it appears The cancellation seems to happen, you know for any value of n, right? So it's not something that you know you need to put in in advance and how I Mean we can discuss it later, but you know the other Interesting thing is that you know if you now compute the In the long wavelength limit you compute the single single magnum dispersion You get of course the linear dispersion, you know you get the your custom modes and you get some velocity is You know around the gamma point is given by this value with Small decay that this is proportional to q squared So now you can go and compare right this a spring wave velocity versus You know the spring wave calculation actually with a non-linear correction and You know what you get is that you know the both around the gamma point and the plus minus k point This spring wave velocities actually turn out to be very similar. So somehow you reproduce pretty well the You know the hydrodynamic limit that as I said, you know, you know, it's well described by the one over as expansion so the other Check that you know one can run is simply compute the order of moment You can compute the order of moment by taking the derivative of the ground state energy as a function of this symmetry breaking field and You know you can do this calculation different ways You know you have to be careful because you know here you have zero modes associated with this gauge invariance So you can either use for that pop off or you can truncate your fluctuation matrix in both cases You get the same result What you get is that the order of moment is 0.22 the full moment is 0.5. So basically This number is quite close actually to values that we're obtained, you know with different numerical approaches This is density matrix normalization group. This is quantum Monte Carlo and this is serious expansions If at the cell point level you get 0.28 and with no linear spring waves you get 0.25 The other check is, you know, you can go and compare the magnet dispersion that you obtain with this Basically saddle point plus fluctuations against the result of serious expansions. This was done in 2006 by Rashi Singh and company and What you find out now is that the bandwidth is Roughly 20% bigger the bandwidth of the series expansions is 20% bigger than what you get with this, you know one of an approach The okay, so keeping this in mind now, you know, it's time to go back to the actual compound So far I have described, you know, what happens for the for the 2d limit for the 2d Heisenberg model And you know in that case you have to introduce two additional basic Havart Trotanovic Fields When you do the calculation back to this compound you basically get Now a dispersion a single magnet dispersion that has a bandwidth of 1.3 millilectron volts While the experimental bandwidth is actually 1.6 So you underestimate roughly also by 20% the experimental Finally, I mean in addition to the two magnet modes I mean here one of the magnets is over damped you get this high-energy continuum here That corresponds to the spin to spin on continuum and you know may be connected to this high-energy Continuum that is observed in Tanaka's experiment Actually, the the the experimental continuum extends up to you know, higher energies even higher energy Higher energies than the two spinon and finally So to conclude, you know, let me say that you know one can reproduce pretty well at least in this qualitative aspect of the High-energy part of the continuum of you know of this material Using this one over n approach But you know keeping going beyond the saddle point level the magnet dispersion is roughly 20% lower In bandwidth that what you will get You know with you know in the experiment You get a qualitative improvement related to saddle point right because you get this removal of of the spurious modes and then In addition you get this extended to spinon continuum You get correct order moments and magnum velocities in the in the long wavelength limit and something that you know I didn't have time to discuss which is that you know, you can reproduce the You know, basically if you take the large s-limit in this approximation So in the constraint you put s very large you get exactly the result of spin waves So basically you reproduce spin waves in the large s-limit Thank you for your attention