Thousands of kilometers away, quantum entanglement is still there. China experiment answers Einstein’s puzzle
China continues to lead in quantum communication research.

　

　　On June 16th, Chinese scientists took the lead in successfully realizing the two-way quantum entanglement distribution between the satellite and the ground in the world by using the "Mozi" quantum science experimental satellite, and on this basis, they realized the nonlocality test of quantum mechanics that strictly met the "Einstein localization condition" on the spatial scale, which laid a reliable technical foundation for the future experimental research on large-scale quantum networks and quantum communication, as well as the experimental test of the basic principles of physics such as general relativity and quantum gravity in outer space.

　

This achievement was made by a research team composed of Pan Jianwei, a professor at China University of Science and Technology, and Peng Chengzhi, a colleague, in collaboration with Wang Jianyu Research Group of Shanghai Institute of Technical Physics, Institute of Microsatellite Innovation, Institute of Optoelectronic Technology, National Astronomical Observatory, Purple Mountain Observatory, National Space Science Center, etc., with the support of the strategic pilot science and technology project of space science of China Academy of Sciences. On the same day, relevant achievements were published in the international authoritative academic journal Science in the form of cover papers.

　

Two entangled quanta, no matter how far apart, can affect each other instantly.

　

On August 16th, 2016, China successfully launched the first quantum science experimental satellite "Mozi", which is one of the first scientific experimental satellites in the space science pilot project of China Academy of Sciences.

　

Quantum is the smallest and indivisible unit of energy in the physical world. Quantum entanglement is one of the two wonderful properties of quantum. "It is a quantum state composed of two (or more) particles. No matter how far apart the particles are, measuring one of them will inevitably affect other particles. Two entangled quanta are like a pair of telepathic twins. No matter how far apart they are, on the order of thousands of kilometers or more, as long as the state of one of them changes, the state of the other person will also change. " Pan Jianwei said, "This phenomenon is called nonlocality of quantum mechanics. The nonlocality of quantum entanglement is one of the most magical phenomena in quantum mechanics. "

　

Einstein called quantum entanglement "ghostly action at a distance", and he thought that this effect may be manipulated by some so-called "hidden variable" that people may not understand for the time being. So, is Einstein right?

　　

In 1964, physicist john bell put forward an experimental scheme, which can be tested. "This is the quantum entanglement distribution experiment. Let a machine emit the prepared pairs of entangled particles (usually photons) in two directions, and then randomly measure the polarization direction of entangled photons at different angles. " Peng Chengzhi, a researcher at the University of Science and Technology of China, the chief engineer of the scientific application system of the quantum science experimental satellite and the deputy chief engineer of the satellite system, said, "If the measurement results meet the Bell inequality, Einstein is right; Otherwise, it is proved that the nonlocality of quantum mechanics is real. "

　　

To verify whether quantum entanglement exists at a longer distance, we need to experiment in space.

　　

In the quantum entanglement distribution experiment, in order to ensure the space-like separation of measurement events, scientists always place two detection devices at a certain distance. Every time they finish a round of experiments, they will think, if the distance is farther, does quantum entanglement still exist?

　

However, because quantum entanglement is very fragile, it will decay with the transmission distance of photons in optical fiber or in the surface atmosphere. In other words, if this experiment is done on the ground, the transmission distance cannot be too long.

　

"Even with the most advanced ideal single-photon detector, point-to-point quantum communication in 1200 km optical fiber can only transmit one bit every 30,000 years. Just like a team with 1 million people, there may be only a few people left in the end, and it took a long time to reach the destination. " Pan Jianwei said, "This leads to the low efficiency of information transmission over a long distance, so the previous quantum entanglement distribution experiment only stayed at a distance of 100 kilometers."

　

How can we further extend the distance of quantum entanglement distribution? Pan Jianwei said that there are two ways in theory at present. One is to use quantum relay, that is, to divide the transmission into several segments to reduce the loss of each segment, and solve this problem by means of "quantum relay". However, at present, this approach is still seriously restricted by factors such as quantum storage life and readout efficiency, so it can not be applied in practice.

　

"The other is to use the satellite platform. Because in space, there is basically a vacuum near the orbit of the satellite, and most of the air is attached to the surface of the earth. Therefore, if entangled photons are emitted from space to the ground, the interference will be relatively small and the loss will be small. Combined with the transfer of satellites, it is expected to realize ultra-long-distance quantum entanglement distribution on a global scale. " Pan Jianwei said, "Our research team decided to use this way to extend the distance of quantum entanglement distribution, and in 2003, we proposed a scheme to realize long-distance quantum entanglement distribution by using satellites."

　

When the satellite transits through the border, it realizes the two-way quantum entanglement distribution between the satellite and the ground in 1200 kilometers.

　

How is this experiment conducted?

"When the Mozi crossed the border, it established optical links with two ground stations, Delingha Station in Qinghai and Gaomeigu Station in Lijiang, Yunnan." Wang Jianyu, a researcher at Shanghai Institute of Technical Physics, Chinese Academy of Sciences, executive deputy chief engineer of quantum science experimental satellite engineering and commander-in-chief of satellite system, said that the entanglement source load on the satellite generates 8 million entangled photon pairs per second, and the establishment of optical link can establish quantum entanglement between two stations over 1,200 kilometers on the ground at the speed of one pair per second, and the transmission attenuation of this quantum entanglement is only one trillion times that of the lowest loss ground optical fiber of the same length.

　　

Pan Jianwei said: "Under the condition of closing the localization loophole and measuring the selective loophole, the experimental results we obtained violated Bell’s inequality with four standard deviations, that is, the quantum mechanical nonlocality test that strictly meets Einstein’s localization condition was realized on the spatial scale of thousands of kilometers."

　

Reviewers of Science magazine praised the achievement as "a major technological breakthrough with potential practical application and the importance of basic scientific research".

　

Pan Jianwei said that using the developed quantum entanglement distribution technology, the research team is conducting experiments to create keys to realize information transmission between heaven and earth. At present, one of the main challenges of quantum communication is how to distinguish and receive the signals of quantum satellites when there are a large number of optical photons in the daytime, so as to realize quantum communication. Other important scientific experimental tasks of Mozi satellite, including high-speed satellite-ground quantum key distribution and teleportation of satellite quantum, are also under intense and smooth progress. It is expected that more scientific achievements will be released one after another this year.

　

Our reporter Wu Yuehui People’s Daily (June 17, 2017, 04 edition)

　http://paper.people.com.cn/rmrb/html/2017-06/17/nw.D110000renmrb_20170617_7-04.htm

　　China News Service, Neijiang, Sichuan, September 8 (Reporter He Yuqing, Liu Zhongjun) The reporter learned from the Sichuan Earthquake Administration on the 8 th that the comprehensive analysis of experts believes that the Sichuan Weiyuan M 5.4 earthquake belongs to a tectonic earthquake, which occurred near the Lijiachang fold in the southeast wing of Weiyuan anticline, and it is unlikely that a larger earthquake will occur in the earthquake zone in the near future.

　　China Seismological Network officially determined that an earthquake of magnitude 5.4 occurred at 6: 42 on September 8 in Weiyuan County, Neijiang City, Sichuan Province (29.55 degrees north latitude and 104.79 degrees east longitude) with a focal depth of 10 kilometers.

　　From the 5.4-magnitude earthquake in Weiyuan to 12: 00, 14 aftershocks of M2.0 and above were recorded locally. Among them, there was one earthquake of magnitude 4.0 to 4.9 and 13 earthquakes of magnitude 2.0 to 2.9.

　　As of 14: 50 on the same day, the earthquake caused one death and 53 injuries; 49 towns and villages were affected by the disaster, with 1,133 people affected, 86 houses collapsed, 194 houses were seriously damaged and 2,098 houses were slightly damaged.

　　The power communication in Longhui Town, Weiyuan County, the epicenter of the earthquake, was normal, and street shops were still open to welcome guests. Although the tranquility of this town was "broken" by the sudden earthquake in the morning, people’s lives seem to have not changed much.

　　After the earthquake, Peng Qinghua, secretary of the Sichuan Provincial Party Committee, demanded that the earthquake disaster be quickly verified, that all efforts be made to treat the injured, that the affected people be properly transferred and resettled, and that the basic livelihood be effectively guaranteed. It is necessary to organize professionals to conduct safety assessment and appraisal of housing, and start reinforcement, maintenance and reconstruction work in time. It is necessary to immediately investigate the hidden dangers of geological disasters in the earthquake zone, ensure the safe and smooth infrastructure such as transportation, electricity, water conservancy and communication, and prevent new losses caused by secondary disasters. Yin Li, governor of Sichuan Province, led a working group and rushed to the earthquake site to guide the rescue work.

　　Since 1900, there have been 8 earthquakes (including aftershocks) of magnitude 5.0 or above within 100 kilometers of the epicenter of this Weiyuan M 5.4 earthquake. Among these earthquakes, the largest one was the Mabian M5.5 earthquake in Sichuan on May 16, 1936 (about 100 kilometers away), the latest one was the M5.2 earthquake in Rongchang District of Chongqing on August 13, 1997 (about 75 kilometers away), and the latest one was the M5.0 earthquake in Zigong City, Sichuan Province on October 24, 1954, with a spatial distance of about 17 kilometers. (End)

Special feature of 1905 film network Every Friday, the world’s best films in Universal Cinema continue to be broadcast, and on May 5, the film "007 Breaking the Sky" will be broadcast for you.

James Bond failed in his mission? See how he strikes back.

As a masterpiece commemorating the 50th anniversary of 007 series, The Story of 007 is the first IMAX film in the history of 007, and also the third 007 starring the sixth generation of 007 actors.

In 2013, the film "007 Breaking the Sky" was shortlisted for three nominations, including the 85th Best Photography, and finally won the Best Original Song Award and the Best Sound Editing Award.

The image of this "gentleman" agent, which has been passed down for more than 50 years, has long been deeply rooted in the hearts of the people.

Wonderful stories, carefree movements, cool cars, beautiful bond girl and many other elements have made the 007 series films enduring after six generations of actors.

The honor of the nomination of "Best Photography" made more people pay attention to the lens performance of "007 Breaking the Sky".

As the director’s first attempt at an action film, this film is often shot by multiple machines at the same time.

In an outdoor scene shot from Istanbul, four cameras were used, one near daniel craig, one for the middle shot, one for the distant view, and the last one moved as needed.

In the dark corridor, a beam of light hits Bond’s face. This contrast between light and shade not only highlights the director’s precise use of lens and light, but also depicts Bond’s cold agent image delicately.

The film’s "ride" is of great concern to viewers who are both fans of 007 movies and car fans.

In the film, the 1963 Aston Martin DB5 driven by James Bond pays tribute to the DB5 that first appeared in the 1964 film "007: Goldfinger", and even the license plate number is the same, which is also the most famous of all Bond cars.

In the previous 007 movies, DB5 has many high-tech equipment added by Dr. Q, including bulletproof body, fuel nozzle, smoke launcher, machine gun, rotating license plate, tracking device receiver, and the most popular ejection seat.

The return of this traditional Bond car also makes Dr. Q’s return in "007 Breaking the Sky" more logical.

The most heartbreaking part of this film is Mrs. M’s "leaving".

In 1995, the actor began to play the role of "Mrs. M" in the 007 series movies. After a lapse of 17 years, Mrs. M, who she played, finally made a curtain call in "007".

As the direct leader of James Bond, Mrs. M is not loved by "subordinates", but gives people a sense of severity, rigidity and inhumanity, and often criticizes Bond.

Although on the surface, the two men are often "at odds", Bond respects M very much, and M is proud of having such a good staff, often praising him in front of others, and thinks that Bond is the best of all agents.

Mrs. M’s curtain call in the film was called "Real bond girl" by many fans.

After more than half a century, the legend of James Bond continues. With handsome image, straight suit and excellent ability, 007 has long been not only a movie and a code name, but also a hero that many viewers yearn for.

At 22:20 on May 5, lock in the movie channel Universal Cinema to see how Bond can get back on his feet after the injury and stop the shocking plot.

　　CCTV News:At present, winter vegetables are listed one after another. All localities should do a good job in ensuring the supply of vegetables in winter, keep the "vegetable basket" of the masses, and ensure sufficient supply of vegetables and stable prices.

　　According to the vegetable production information dispatch of the Ministry of Agriculture and Rural Affairs, at present, the vegetable field area in China is 88.48 million mu, an increase of 1.15 million mu year-on-year; In late November, the output was 29.61 million tons, an increase of 750,000 tons.

　　Shenxian county is an important vegetable planting area in the north of the Yangtze River, and the local annual vegetable output reaches more than 5 million tons. The reporter saw in the agricultural products trading market in Shilipu Town that at dawn, local vegetable farmers came to the vegetable trading market early to sell all kinds of vegetables just picked.

　　At present, in the demonstration industrial base of returning entrepreneurs in Dongxiang District, Fuzhou City, Jiangxi Province, more than 4,000 mu of Phyllostachys praecox bamboo shoots have ushered in the harvest period. The villagers are busy collecting, sorting, loading and exporting, and the harvesting period will last until the end of March 2024.

　　At present, in Shaohuomiao Village, Chuanhui District, Zhoukou City, Henan Province, the edible fungi planted in the intelligent cabin are welcoming the harvest season. Due to the computer control of temperature and humidity in the process of edible fungi cultivation and scientific management, the annual income of the two cabins can reach about 100 thousand yuan.

　　In order to ensure the continuous and efficient supply of vegetables in winter, Shenzhou City, Hebei Province set up 20 vegetable technical guidance groups to scientifically guide growers to plant in succession, so that the greenhouse will not be idle in winter and the supply of vegetables will be uninterrupted.

　　Various measures have been taken to prevent cold wave and ensure vegetables to survive the winter smoothly.

　　In view of the recent cold wave weather in many parts of the country, the production and supply of vegetables are facing challenges. All localities actively take scientific measures to do a good job in cold protection and warmth to ensure the smooth wintering of all kinds of vegetables.

　　In Hengyuan Street, Linyi County, Shandong Province, in order to cope with the sharp cooling and strong wind brought by the recent cold wave weather, the local government sent meteorological service information to vegetable farmers in a targeted manner and provided "point-to-point" assistance. According to the growth situation of different vegetables, it provides targeted scientific anti-freezing schemes for vegetable farmers to ensure the smooth listing of vegetables.

　　In the vegetable greenhouse in Maozhuang Town, Taikang County, Henan Province, agricultural technicians are checking the growth of vegetables and urging farmers to do a good job of heat preservation and antifreeze to avoid the sudden drop in temperature from affecting the growth of vegetables.

　　In Huai ‘an District, Huai ‘an City, Jiangsu Province, in order to cope with the coming cold wave, Yao Bingqing, a big planter, is busy covering 31 newly installed facilities in 2023 with two or three films before the rain and snow, and strengthening the cold protection measures through "three films".

　　The seasonal decline in the overall price of vegetables is expected to pick up later.

　　Affected by factors such as area increase and yield increase, the overall price of vegetables has fallen seasonally, and some varieties are significantly lower than the same period in 2022.

　　Haijixing International Agricultural Products Logistics Park, located in Changsha County, Hunan Province, is the largest vegetable hub in Central and South China. Vegetables from more than 20 provinces in China gather here, and more than 10,000 tons of vegetables are sent from here to Guangdong, Guangxi and other provinces and regions every day, ensuring the vegetable supply of residents within 600 kilometers.

　　According to the relevant person in charge of the Ministry of Agriculture and Rural Affairs, recently, the prices of some vegetable varieties have fallen sharply, mainly due to the high price in 2022. In 2023, the planting area increased steadily, the weather in autumn and winter was warmer, the yield level was significantly improved, and the local vegetables were listed on the market, and the staged supply pressure increased. From the later trend, vegetable prices will turn into seasonal upward trend according to the perennial law.

　　Near New Year’s Day and Spring Festival, the holiday effect is gradually emerging, and the demand for vegetable consumption is expected to increase. Because vegetables have increased steadily in the field area, winter storage vegetables such as cabbage and radish have increased in the early stage, the overall supply of vegetables is guaranteed, and it is unlikely that the price of vegetables will rise sharply.

　　have/reap a bumper/copious/rich harvest

　　Less than a month before the 2023 college entrance examination, the college entrance examination work was put on the agenda. On May 9, the Ministry of Education and relevant departments held a video conference on the safety of the 2023 national college entrance examination. The Minister of Education made arrangements for the 2023 college entrance examination, emphasizing the prevention of cheating on mobile phones as the top priority of this year’s college entrance examination.

　　This year’s college entrance examination is the first one after the Covid-19 epidemic, which means that the epidemic has little impact on the college entrance examination, and we will concentrate on the "safe college entrance examination". One of the arrangements for the "Safe College Entrance Examination" is to strengthen comprehensive management, and preventing mobile phone cheating is the top priority of this year’s college entrance examination security. To this end, the Ministry of Education emphasizes that mobile phones cannot be brought in, used or sent out.

　　The reason why preventing mobile phone cheating is the top priority of college entrance examination security is because everyone has a mobile phone today. If the prevention is not strict, the mobile phone will easily become a cheating tool. More importantly, in recent college entrance examinations, although it is explicitly forbidden for candidates to bring wireless communication devices such as mobile phones into the examination room before the college entrance examination, and metal detectors are supplemented during security inspection, and various measures are taken to shield wireless signals, mobile phone cheating cases still occur.

　　For example, in the college entrance examination in 2021, a candidate in Hubei illegally brought his mobile phone into the examination room. In the examination, he hid the mobile phone under the draft paper to shoot questions, and distributed it to a training institution to seek answers at the beginning of the examination. In the college entrance examination in 2022, a candidate in Gansu illegally brought his mobile phone into the examination room. After the examination, he took the test paper and sent it to QQ group for an answer. These events have aroused social concern and affected the reputation of the college entrance examination.

　　The college entrance examination is a life test for the majority of candidates. Only a standardized college entrance examination order can ensure the fairness of the college entrance examination. Although the mobile phone cheating in the above cases failed to achieve the goal, it still revealed that the security of the college entrance examination seemed to be well deployed, but in fact there were some loopholes. In order to maintain the fairness and justice of the college entrance examination, preventing mobile phone cheating has been mentioned in an important position in this year’s college entrance examination.

　　The so-called "no entry" is to strengthen the security inspection of test sites and prevent candidates from bringing their mobile phones into the examination room from the source. If the security personnel of the test center are serious and responsible for their work, and with the help of advanced technology such as metal detectors, candidates with mobile phones can be found in time and prevented from entering the examination room.

　　"I can’t use it" means to strengthen the responsibility of the invigilator in the examination room. Even if candidates carry their mobile phones through the security clearance, they will not have the opportunity to use them in the examination room, which is a supplementary defense against possible security omissions. "Unable to transmit" means to improve and upgrade the wireless signal shielding equipment, so that even if candidates use mobile phones in the examination room, they cannot achieve the purpose of obtaining answers.

　　In order to maintain the order and fairness of the college entrance examination, this year, the safety of the college entrance examination was clearly defined, and specific requirements were put forward to form a "full chain" supervision at the test sites. The effect is worth looking forward to. First, "taking the prevention of mobile phone cheating as the top priority of the college entrance examination this year" is a shock to candidates with cheating tendency. Second, this will further compact the supervision responsibility of the three links and ensure that mobile phone cheating cases will not appear.

　　However, considering that the total number of candidates is likely to exceed 10 million this year, the number of candidates in some provinces has increased, and the idea that individual candidates still cheat on mobile phones is not ruled out. At the same time, considering that there are as many as seven or eight thousand test sites in the national college entrance examination, it is not excluded that there are omissions in the security inspection of individual test sites. In addition, there are hundreds of thousands of college entrance examination rooms every year, and there are more than one million invigilators, not to mention the negligence of invigilators.

　　After the Ministry of Education emphasized that preventing cheating on mobile phones should be the focus of this year’s college entrance examination security, all localities must make further detailed arrangements to truly pursue secrecy and prevent one from being sparse. There are still more than 20 days before the college entrance examination. I hope that all relevant departments at all levels, the person in charge of each test center and each invigilator can make full preparations, strictly perform their duties and responsibilities, guard the discipline and fairness of the college entrance examination, and hand over satisfactory answers to the majority of candidates and the public.

　　Photo courtesy/vision china