CHINA DAILY | HONG KONG EDITION Monday, December 14, 2020 | 5 CHINA Ghost particle probe Water fall marks end of an era

Shenzhen facility decommissioned after 9 years of research into universal puzzle

By ZHANG ZHIHAO in Shenzhen, Guangdong [email protected]

Chinese scientists have decom­ missioned the Daya Bay Reactor Neutrino Experiment in Shenzhen, Guangdong province, bidding farewell to a major scientific Guests look at four neutrino detectors at the Daya Bay Reactor A helicopter participates in a forest fire extinguishing mission during an exercise in Nanchang, Jiangxi instrument responsible for one of Neutrino Experiment in Shenzhen, Guangdong province, during a province, on Saturday. The drill featured nearly 1,000 firefighters, including three helicopter crews. China’s biggest discoveries in phys­ ceremony for its decommissioning on Saturday. MAO SIQIAN / XINHUA LIU ZHANKUN / CHINA NEWS SERVICE ics that may help explain why the universe is the way it is. through space. After decades of JUNO will use an equally awe­ A mission completion ceremony experiments, scientists had meas­ inspiring design. Its central detect­ was held on Saturday at the facility, ured two of the three “mixing or will consist of a 35.4­meter which was first conceived in 2003. angles” which, crudely speaking, diameter, 12­centimeter­thick Launched in 2011, the instrument describe the degree to which one transparent acrylic sphere, the big­ Three net science award in Shanghai has finished all its research mis­ flavor can mix into another. gest of its kind in the world, hold­ sions and produced valuable data The final mixing angle was ing 20,000 tons of liquid By ZHOU WENTING possible application in quantum with unprecedented precision. determined by the international scintillator, a solution that exhibits and CAO CHEN in Shanghai computers, Kane said one idea is to China’s next­generation neutri­ team of researchers at the Daya flashes of light when excited by take advantage of the special proper­ no detector — the Jiangmen Bay Reactor Neutrino Experiment ionizing radiation. The development of a revolution­ Loads of efforts should ties of the topological insulators. Underground Neutrino Observa­ in 2012. The discovery opened the The sphere will be submerged in ary material that may help propel be made, including “China is making enormous invest­ tory, or JUNO — is being built 700 door to probing whether there is a a tank holding 30,000 tons of ultra­ today’s digital products into a new era ment in academic infrastructure to meters underground in Jiangmen, slight asymmetry between neutri­ pure water and be surrounded by is being accelerated, with laboratories manufacturing, build up research capabilities, and Guangdong. The 2 billion yuan nos and antineutrinos, the mirror tens of thousands of detectors. The in many countries contributing to the discovering better that investment will pay off,” he said. ($305.3 million) instrument is image of neutrinos that have the cave to hold all the instruments effort, scientists said. Xue’s lab has been conducting expected to be completed around same mass and no charge, but will need to be 50 meters in diame­ The material — a topological insu­ materials that have a basic research in topological geome­ 2022, with around 680 researchers with opposite chirality. ter and 70 meters tall. lator that insulates the interior of a lower cost and are try for years and has made ground­ from 18 countries and regions par­ When a particle and its antiparti­ It is hoped JUNO will discover semiconductor while supporting the easier to produce, breaking discoveries. ticipating in the project. cle collide, they typically annihilate more about the masses of neutri­ flow of electrons — may also help real­ One of its latest research break­ The new machine aims to detect each other and release energy, nos, including their ordering, ize the dream of more­efficient quan­ developing related throughs is increasing the tempera­ and measure neutrinos with according to the journal Science. Wang said. It will also be able to tum computers, said Charles L. Kane, technology and ture at which the new material can be unprecedented precision and Scientists have theorized that there measure the three types of neutri­ a professor of physics at University of effective from around ­273.12 C to energy resolution, hoping to should be an equal amount of parti­ no oscillations with greater preci­ Pennsylvania in the United States. boosting the supply of ­270.15 C by optimizing materials, he uncover more insights on their cles and antiparticles produced sion. Kane and two other scientists — raw material.” said. mass, how they can change identi­ shortly after the Big Bang, yet for “For a long time, physicists Michael V. Berry, a professor of phys­ His team also discovered a new ties midflight in a process called some unknown reasons the uni­ thought neutrinos had no mass, ics at University of Bristol in the Unit­ Xue Qikun, material scientist synthetic magnetic material, which oscillations and solve more mys­ verse has evolved to have signifi­ but if that is the case, then the uni­ ed Kingdom, and Xue Qikun, a and Fudan­Zhongzhi Science may be “much easier to be realized teries about the perplexing ele­ cantly more matter than antimatter. verse cannot form the structure as professor of physics at Tsinghua Uni­ Award winner and applied in semiconductors in the mentary particle, which is both The results sent a shock wave it is today,” he said. “Because of versity in Beijing — were awarded the future than previous materials”. extremely abundant and difficult through the world’s physics com­ neutrinos, we exist. 2020 Fudan­Zhongzhi Science Award However, the scientists said they to spot. munity, with the journal hailing it Wang said JUNO will make Chi­ for their extraordinary contributions moving to the other side,” Kane told have no idea how long it will take for The engineering breakthroughs as one of the biggest break­ na one of the world’s front­runners to research in topological geometry. China Daily ahead of the awards cere­ the promising material to actually that made observation possible throughs in 2012. Lee Tsung­Dao, in neutrino research technology, A ceremony was held at Fudan Uni­ mony. be brought into being, and its ulti­ can also benefit society and indus­ a Nobel laureate in physics, said in comparable only to the United versity in Shanghai on Sunday, with “But the flow of the electrons in a mate application may be something tries in the form of ultrasensitive a congratulatory letter that it rep­ States’ Deep Underground Neutri­ the two scientists from abroad partic­ surface conductor with the new they haven’t thought of. light detectors, new manufactur­ resents a major achievement in no Experiment and Japan’s Hyper­ ipating through video linkups. material is much more organized. It’s “Loads of efforts should be made, ing techniques and standards for physics with key significance for Kamiokande, both of which are set Fudan said Berry was given the like a highway with divided lanes including manufacturing, discover­ high­performance steel and glass, basic research. to be operational in 2027. award for the theoretical discovery of going both directions.” ing better materials that have a lower and ultraclean water for the semi­ “While there have been numer­ “JUNO will complement the oth­ the geometric phase, widely known Kane said this helps lessen heat cost and are easier to produce, devel­ conductor industry. ous breakthroughs in our under­ er neutrino observatories both in as the “Berry phase”, in basic quan­ production and energy waste, which oping related technology and boost­ “The Daya Bay Reactor Neutri­ standing of neutrinos in the past their mission objectives and time­ tum mechanics. Kane was recognized may affect the speed and efficiency of ing the supply of raw material,” Xue no Experiment laid the foundation few decades, there are still many line,” he said. In the past, Chinese for his pioneering contributions in a digital device. said. of China’s international coopera­ questions left unanswered,” Wang scientists often took part in big sci­ the field of topological insulators, and When electronics are made small­ The Fudan­Zhongzhi Science tion in neutrino­related particle said. “Answering them may funda­ entific experiments hosted by oth­ Xue received his award for his discov­ er, the problem of disorganized elec­ Award was jointly founded by Fudan physics and paved the theoretical mentally change how we under­ er countries, but now they are ery of the quantum anomalous Hall tron motion gets worse, making the University and the Zhongzhi Enter­ groundwork for new neutrino stand particle physics and the capable of launching, organizing effect, which promotes the organized heat problem more obvious, he add­ prise Group in 2015 to recognize sci­ observatories being built in China evolution of the universe.” and managing major scientific flow of electrons in a system without ed. entists who have made fundamental and around the world,” said Wang projects that can attract global par­ the use of an external magnetic field. Berry, who discovered his name­ and groundbreaking achievements in Yifang, director of the Chinese Seeing the invisible ticipation, which speaks volumes Kane explained that based on the sake “Berry phase”, a general idea that the fields of physics, mathematics and Academy of Sciences’ Institute of To detect something as elusive as for China’s scientific development, “Berry phase”, the novel material will has applications in various branches biomedicine. High Energy Physics. a neutrino requires extraordinary he added. theoretically make semiconductors of physics, in 1983, said, “the new Each year, the laureates share a A neutrino is a subatomic parti­ engineering, bordering on science However, it is hard to predict more efficient. material would have very different prize of 3 million yuan ($459,000), cle produced by radioactive decay, fiction, and physicists often when the next big discovery will “One problem about the current electric and magnetic properties, which is donated by Zhongzhi Enter­ a process commonly found in the describe such projects as extreme occur since neutrinos rarely inter­ ones is that electrons flowing inside which all types of applications in tran­ prise. nuclear reactions of our sun or in precision measurement on an act with anything and are so hard constantly bump into things. It’s like sistors, cellphones and computers nuclear power plants. It carries no extreme scale. to detect. “There is quite a bit of you’re in a crowded room and you may need.” Contact the writers at electrical charge and has minus­ One notable example is the luck involved,” Wang said. constantly crash into things when Speaking about the new material’s [email protected] cule mass, at least a million times Super Kamiokande detector, locat­ Over its estimated 30­year oper­ smaller than an electron, Wang ed 1,000 meters underground ational life, JUNO hopes to record said, “yet it is a fundamental inside Mount Ikenoyama in Japan, a supernova explosion in our gal­ building block of our physical which was launched in 1996. It fea­ axy, which happens only around Scientists’ profiles reality.” tures a 15­story­tall, stainless­steel once a century. These properties allow neutri­ tank holding 50,000 metric tons of A supernova is the explosion of a nos to penetrate most matter and ultrapure water, which is moni­ massive star at the end of its life Michael V. Berry, Charles L. Kane, Xue Qikun, born rarely interact with any of them, tored by around 13,000 photomul­ and is capable of releasing more born in England in born in the United in China in 1963, is not even with light. Hence, the tiplier glass bulbs, each half a energy than the total output of the 1941, is a professor States in 1963, is a a professor in the particle cannot be felt or seen meter in diameter, installed on the sun in 10 billion years, making it of physics at the Uni­ professor of physics at physics depart­ despite trillions of them passing tank’s wall. one of the brightest and most pow­ versity of Bristol in the University of Penn­ ment at Tsinghua through our bodies at near­light The facility is built underground erful events in the universe. the United Kingdom. sylvania. He was University. He was speed every second, Wang said. to eliminate interference from oth­ “Around 99 percent of the super­ He was knighted in awarded the 2010 awarded the 2016 Therefore, the neutrino is also er particles. When a high­energy nova’s energy is released in the 1996 and is a recipient of the 1998 European Physics Prize for Condensed Future Science Prize in physical sci­ humorously referred to by scien­ neutrino collides with the atomic form of neutrinos within a dozen Wolf Prize in Physics, the 2001 Onsa­ Matter Physics, the 2012 Dirac Medal, ence, the First Prize of the State Natu­ tists as the ghost particle. nucleus of the water, the detectors seconds, some of which will show ger Medal and the 2015 Lorentz Med­ the 2012 Oliver Buckley Prize of Ameri­ ral Science Award of 2018 and the What is more perplexing about will register a faint light known as up on our detectors as a burst of al. can Physical Society, the 2015 Franklin 2020 Fritz London Memorial Prize for the particle is that since its discov­ Cherenkov radiation, signaling events,” Wang said. “This will give Berry is best known for his discovery Medal and the 2019 Breakthrough low­temperature physics. ery in 1956, scientists have found that a neutrino has been found. us more opportunities to study the of the geometric phase in basic quan­ Prize in Fundamental Physics. Xue’s research has centered on top­ three different types, or “flavors”, But even with this degree of engi­ supernovae explosion mechanism tum mechanics. He pointed out the Kane’s research has focused on the ological insulators, interface­induced of neutrinos that can transform neering, identifying a neutrino is and potentially lead to new discov­ non­integrable phase factor of quan­ quantum condensed matter theory. He high­temperature superconductivity, into one another when traveling still exceedingly rare. eries about the cosmos.” tum states in an adiabatic and cyclic is responsible for most of the key theo­ molecular beam epitaxy and surface process. retical concepts that have generated science. The discovery of the non­integrable topological insulators, as well as the He is best known for the experimen­ Stadium all set phase factor is a fundamental break­ ensuing broader investigation into the tal discovery of the quantum anoma­ through in quantum mechanics, and is topological features of electron struc­ lous Hall effect, the realization of A renovation project for the widely known as the “Berry phase”. It ture. which was highly challenging. It took National Indoor Stadium is serves as a basic concept to under­ His and his colleagues’ proposition 25 years to realize the prediction that completed in Beijing on Satur­ stand some of the most important sys­ of a quantum spin Hall effect without was first proposed in F. Duncan M. day. It is the second venue in tems in condensed matter physics, external magnetic fields led to the the­ Haldane’s toy model in 1988. The pre­ the capital to complete renova­ such as the topological insulator and ory of topological insulators. Due to his cise quantization of the Hall conduct­ tion work in preparation for the the quantum Hall effect, which are pioneering theoretical work, topologi­ ance in the absence of an external 2022 Winter Olympic Games. characterized by a quantized Berry cal insulator materials and their deriva­ magnetic field makes the quantum The first was the National phase. tives have been proposed in theories anomalous Hall effect one of the most Aquatics Center, or the Water and discovered in experiments, and remarkable discoveries in condensed Cube, which was used during they currently form an active and matter physics since the discoveries the 2008 Summer Olympic important sub­field in condensed mat­ of the quantum Hall effect and the Games. The stadium will host ter physics. fractional quantum Hall effect. some ice hockey games. XIA SHIYAN / FOR CHINA DAILY