Two scientists from Dongyang, Zhejiang Province, stand behind the “nine chapters” of China’s photonics computer! The world’s fastest computer is 600 million years old. It only takes 200 seconds!

In a specific track, the “quantum computing power” of 200 seconds is equivalent to the 600 million year computing power of the “strongest supercomputing” at present. On December 4, the magazine announced a major breakthrough in China’s “nine chapters”. < p > < p > this 76 photon quantum computing prototype developed by Pan Jianwei, Lu Chaoyang and other scholars from the University of science and technology of China, is the first quantum computer to realize “quantum superiority”, and promote the frontier research of global quantum computing to a new height. Although there is still a long way to go before practical application, it has successfully achieved a milestone breakthrough in the “superiority of quantum computing”. < p > < p > traditional computers store all data as 0 or 1, while quantum computers, using the principle of quantum mechanics, can allow an object to be in multiple states at the same time and implement “parallel computing”. Because of this ability, scientists believe that in the face of the computing power that quantum computers may possess in the future, traditional computers will be out of reach. < p > < p > last September, Google announced that it had developed a 53 qubit computer “sycamore”. It only took 200 seconds to calculate a mathematical problem, while the “peak” of the world’s fastest supercomputer at that time took 10000 years, so they realized “quantum superiority” for the first time in the world. Sundal Pichai, CEO of Google, said that the achievement’s status in the history of quantum computing was comparable to the successful 12 second first flight test flight of Wright brothers when they invented the plane in flight history. The problem solved in Chapter 9 is called Gaussian boson sampling. It is an algorithm to calculate probability distribution, which can be used to code and solve many kinds of problems. < / P > < p > it’s a little bit like the game I played when I was a kid – Galton board. When the ball falls from the top of the mouth, half of the ball may go from the left and half from the right when passing through a nail board. Finally, when many small balls are thrown down, the distribution of small balls in the lower grid will present certain statistical rules. < / P > < p > Gaussian Bose sampling is a quantum version of the Galton plate, the actual situation is more complex, very suitable for quantum computer to solve. After several photons enter the grid, they pass through the interferometer composed of beam splitters. Finally, the outlets are detected and recorded, which is a sampling. After accumulation, the photon number will also have a distribution. Each sampling result corresponds to a probability. All possible sampling results constitute the state space of the output state. < / P > < p > experiments show that when solving the Gaussian boson sampling of 50 million samples, “nine chapters” only takes 200 seconds, while the world’s fastest traditional supercomputer “Fuyue” takes 600 million years. < p > < p > just after Google announced the realization of “quantum superiority”, IBM, the developer of the “pinnacle” of traditional computers, questioned it. They believe that Google’s optimization level is not enough when using traditional computer simulations. According to IBM’s calculation, the traditional computer only takes 2.5 days to get the same result as “Platanus”. This kind of query has been recognized by the industry. Pan Jianwei’s team said that the “quantum superiority” experiment is not an overnight task, but a competition between faster classical algorithms and continuously improving quantum computing hardware. However, in the end, quantum computers will produce computing power that traditional computers can’t match. < p > is faster. Although it is not the same mathematical problem, compared with the fastest supercomputing equivalent, “nine chapters” is 10 billion times faster than “Platanus”. The second is environmental adaptability. “Platanus” needs to operate at minus 273.12 ℃, while “nine chapters” can operate at room temperature except for the detection part which needs minus 269.12 ℃. The third is to make up for the technical loopholes. “Platanus acerifolia” is faster than supercomputing only in the case of small samples, while “nine chapters” is faster than supercomputing in both small and large samples. At present, quantum computing has become the focus of global competition. For example, recently, the European Union announced that it plans to invest 8 billion euro to study new generation of computing power technologies such as quantum computing. < / P > < p > “quantum computers have ultra fast parallel computing capabilities in principle, and are expected to provide stronger computing power support than traditional computers through specific algorithms in the fields of cipher decoding, big data optimization, weather forecasting, material design, drug analysis, etc Pan Jianwei said that in the next step, the team will promote research on photons, superconductors, cold atoms and other technical lines. < p > < p > in 2019, physicist John Persky, who proposed the concept of “quantum superiority”, wrote a review on Google’s achievements. When he first proposed “quantum superiority”, he asked whether large-scale quantum computing was very, very difficult or incredibly difficult? The former means that there are still decades to go, and the latter means that it may be hundreds more years. Google’s achievements have convinced him that human beings are not far away from the large-scale application of quantum computing. < / P > < p > one of the difficulties that the team needs to overcome is high quality sub light source. “For example, it’s easy to drink one sip at a time, but it’s very difficult to drink one water molecule at a time.” Lu Zhaoyang explained that as like as two peas, each photon must be released at the same time, and each photon must be exactly the same. This is a great challenge for high quality light sources. At the same time, the phase-locked accuracy should be controlled within the negative 9th power of 10, which is equivalent to the transmission distance of 100 km, and the deviation should not exceed the diameter of one hair. < / P > < p > in order to verify whether the calculation of “nine chapters” is accurate or not, the team uses supercomputers to verify the calculation results, and the electricity charge is extremely expensive. It will cost 2 million yuan for 40 photons, 4 million yuan for 41 photons and 8 million yuan for 42 photons, which will be astronomical. Scott Aronson, a professor at the University of Texas at Austin, participated in the peer review. Arenson was not satisfied with the initial supercomputing result of 30 photons. It was he who suggested: can we run more than 40 photons? A few weeks later, he got a reply – it cost more than $400000 to verify 40 photons, and the team decided to stop. ‘it’s the most expensive peer review I’ve ever written! Baidu continues to work on quantum computing to lay a solid foundation for new infrastructure construction