库伦作用无尽期,动量蒙卡寄相思

白石道人姜夔,南宋词人,一生布衣游食四方,存词只有80余首,不算高产(虽然他21岁写下的《扬州慢·淮左名都》入选中学语文课本,诸君可以想想自己21岁时在做什么)。但在他43岁那年的正月里,情感不知为何受到了大的扰动,爆发似的一口气写下一组五首《鹧鸪天》(准确地说是从正月初一到正月十六,从第一首《鹧鸪天.丁巳元日》到第五首 《鹧鸪天·十六夜出》),曲折地追怀自己生命中一段年轻的爱情,五首皆为精品。 Continue reading "库伦作用无尽期,动量蒙卡寄相思"

我爱纠缠如秋裤

科学研究当然也是揭示规律性的活动,从事这个行业的,也颇有一些愿意思考的人。有趣的是,在笔者熟悉的量子多体系统的研究中,竟也存在一个和秋裤颇为相像的事物,揭示出量子多体系统中无处不在的量子纠缠这样深刻的道理,让科研从业者中愿意思考的人安心,忘却身边的种种不顺遂,进入“此中有真意”的境界而更加起劲地探索其中的奥妙。他们发现通过秋裤的视角可以揭示量子多体系统从朗道—金兹堡对称性自发破缺,到量子相变,再到拓扑序长程纠缠和范畴对称性等等奇异的现象,秋裤之功善莫大焉。 Continue reading "我爱纠缠如秋裤"

Correlation-Induced Insulating Topological Phases at Charge Neutrality in Twisted Bilayer Graphene

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"

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"

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 "Quantum Material research connecting physicists in Hong Kong, Beijing and Shanghai"

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 "Breakthrough in Understanding Quantum Metals"