Twisted bilayer graphene (TBG) consists of two stacked layers of graphene rotated relative to one another. With a twist angle of about 1.10° the so-called “magic” angle, many unconventional electronic behaviors emerge, including superconductivity and correlated insulators, a type of insulating phase that arises from interactions between electrons. Elucidating the mechanism responsible for these electronic states in magic-angle TBG is a problem at the frontier of quantum materials research. To help solve this problem, we employ an unbiased quantum many-body numerical method (quantum Monte Carlo simulations) to investigate the possible insulating phases of TBG. Continue reading "Correlation-Induced Insulating Topological Phases at Charge Neutrality in Twisted Bilayer Graphene"
Evidence of the topological KT phase of TMGO
Quantum materials are becoming the cornerstone for the continuous prosperity of human society, including the next-generation AI computing chips that go beyond Moore’s law, the high-speed Maglev train, and the topological unit for quantum computers, etc. However, these complicated systems require modern computational techniques and advanced analysis to reveal their microscopic mechanism. Continue reading
蒙蒙卡和张量量
有的童话穿越历史，变成了一个民族心中的文化图腾，如西游记之于中国人，安徒生和格林童话之于欧洲人。有的童话停留的时间稍短，但也是一代人甚至几代人心中共同的启蒙故事，如《星际旅行》、《铁臂阿童木》、《机器猫》甚至《哈利波特》。对中国的孩子来说，尤其是在1980年代至1990年代成长起来的孩子，这样的童话应属皮皮鲁和鲁西西的故事了。Continue reading
The search of non-Fermi liquid
Three passions, simple but overwhelmingly strong, have governed my life: the longing for love, the search of knowledge, and unbearable pity for the suffering of mankind.
—Bertrand Russell
As Russell nicely put it, scientists are often driven by strong passions for the search of knowledge, such search not only benefits the human society, but often times brings the ecstasy to themselves -- the ecstasy for instance of understanding the hearts of men, knowing why the stars shine, and apprehending the Pythagorean power by which number holds sway above the flux -- that is so great that scientists would often have endured the long hours of working and sleepless nights for the pursuit of such joy. Continue reading "The search of non-Fermi liquid"
非费米液体的追寻
夫人之相与，俯仰一世，或取诸怀抱，
悟言一室之内；或因寄所托，放浪形骸之外。
虽趣舍万殊，静躁不同，当其欣于所遇，
暂得于己，快然自足，不知老之将至。——王羲之《兰亭集序》
人的一辈子，乱乱哄哄、热热闹闹，其实很快就过去了。浮名与虚誉、诱惑与利益，很多时候更是在加速这个过程。时间积分之后，烦恼总是大于欢欣的。这样一个悖论，古今中外多少人都看得明白，比如大书法家王羲之，其所言如上所抄录很是通透。Continue reading
神州帽子何其多
在一段悠然慵懒的岁月里，作者一边进行量子蒙特卡洛计算，一边读着二十四史。在量子多体中的呐喊与彷徨中看到了一丝曙光，也在历史的回味与反思中看到当今科研体制下的无奈与坚忍。“学者的贡献在于发扬真理，脱心志于俗谛之桎梏，在于铸造后起的头脑，不在于自己头上有多少帽子。” Continue reading
Quantum Material research connecting physicists in Hong Kong, Beijing and Shanghai
A joint research team from The University of Hong Kong (HKU), Institute of Physics at Chinese Academy of Science, Songshan Lake Materials Laboratory, Beihang University in Beijing and Fudan University in Shanghai, provide a successful example of modern era quantum material research. Continue reading
Breakthrough in Understanding Quantum Metals
Metals, especially interacting metallic states, never stop surprising people. Among the interesting phenomena that have emerged is the “high-temperature” superconductivity. This holds great promise for enabling highly-efficient energy transportation, but it can be achieved only at extremely cold temperatures (about -100 degrees Celsius or below) that are currently too costly and energy-intensive to replicate. Continue reading
一生能有多少爱
我承认，这是一个俗气的题目。
很多年前，大概是还觉得《读者》之类的鸡汤文字集合是文学的时候吧，不知在什么地方见到过以此为题目的一本书。内容自然记不清楚了，大抵都是些content-free 的大实话：人生艰难，痛苦总是多于欢欣，没有爱的扶持我们怎么能够坚持下去云云。时过境迁，已经练就了铁石心肠鸡汤不入，只有这个题目还映在脑海里。Continue reading
历史的终结与最后的人
稍微熟悉一些政治理论的朋友应该都知道弗朗西斯•福山 (Francis Fukuyama)的这本书《历史的终结与最后的人》(The End of History and the Last Man)，此书成于1990年代初，就着当时的时代背景(东欧巨变、苏联解体、冷战结束)预言了人类社会最终的组织形式将会是 liberal democracy。福山先生放眼人类历史上下几千年，剖析波澜壮阔的20世纪，师承从康德、黑格尔到马克思的德国古典哲学与人类社会发展阶段理论，提出“历史终结论”。Continue reading