Researchers are checking the cryogenic processing equipment of quantum computers. People's vision
Speaking of subversive technology, quantum computers are all shining stars in the current scientific and technological field.
"In front of quantum computers, traditional computers are like' abacus'"
Recently, important progress has been made frequently in the field of quantum computers: Honeywell said that a quantum computer with a volume of 64 quanta has been developed, and its performance is twice that of the previous generation; The original quantum computing company in China cooperated with the research team such as the Key Laboratory of Quantum Information of Chinese Academy of Sciences, and found a new idea of controlling and reading quantum bits for the first time in the world, which made it possible to expand quantum bits. ...
What is a quantum computer? Simply put, a device that processes and calculates quantum information and runs quantum algorithms belongs to a quantum computer.
People are full of expectations for quantum computers, which is not unrelated to the bottleneck encountered by traditional computers. In recent years, the performance growth of traditional computers has become more and more difficult, and high-performance computing technology to explore new physical principles has emerged.
"Quantum computer is the inevitable product of chip size breaking through the classical physical limit, and it is a landmark technology in the post-Moore era." Guo Guangcan, academician of the Chinese Academy of Sciences and director of the Key Laboratory of Quantum Information of the Chinese Academy of Sciences, said that in the microscopic state, quantum is an inseparable basic unit. It is well known that microscopic particles such as electrons and photons are all quantum manifestations.
Traditional computers use 0 and 1 to store and process data, commonly known as classic bits. The magic of quantum computer is that its basic computing unit-qubit can be 0 and 1 at the same time, which means that "superposition state" can exist, so it has stronger parallel ability. For example, if you look for a word in 8 million books, the classic computer method is local search, which requires multiple processors to work together to improve the speed. The superposition property of quantum is different from the logic of binary algorithm, so that quantum computers can be searched by 8 million computers at the same time. "In front of quantum computers, traditional computers are like' abacus'." Guo Guangcan said.
According to Zhang Hui, vice president of Benyuan Quantum Computing Company, quantum computers can play an important role in areas requiring large-scale computing, such as helping advanced materials manufacturing and new energy development. In drug research and development, quantum computers can help researchers quickly find anti-virus drugs by accurately simulating the natural evolution of various molecules and atoms; In the field of public transportation, quantum computing can quickly analyze and predict complex traffic conditions, so as to dispatch integrated traffic systems and avoid road congestion to the maximum extent.
The application of quantum computing goes out of the laboratory, benefiting from its engineering progress. At present, many countries regard quantum computing as the commanding height of future science and technology. Well-known enterprises at home and abroad have set foot in quantum computing in succession, and there are more than 100 global quantum computing startups. Guo Guangcan said that the development of quantum computing is faster than expected, and many ideas that stay on paper have gradually become a reality.
"If measured by the development process of classical computers, quantum computers are now in the early' electron tube era'."
Although quantum computer has a broad prospect, its application on the ground still has a long way to go. Guo Guangcan pointed out that to make a quantum computer, three basic conditions need to be met: quantum chip, quantum coding and quantum algorithm. They are the physical systems to realize quantum computing, the processing systems to ensure the reliability of computing, and the key to improve the operation speed.
"To be a quantum computer, you must first have enough qubits." Zheng, a senior researcher at Tencent Quantum Lab, explained. What is a qubit? Theoretically, all carriers with quantum effect in nature can be used as qubits. After long-term exploration, scientists have found that superconductivity, ion traps, photons, ultracold atoms, semiconductor quantum dots and so on all have quantum effects, which means that they can be used to develop quantum computers. These different systems have created different technical implementation routes of quantum computers.
How many qubits should be controlled in the practical application of quantum computer? Zheng said that it is generally believed that 65.438 billion qubits should be controlled. However, at present, the number of quantum bits that can be controlled by industry does not exceed 100.
In the macro environment, how to maintain the quantum characteristics in the micro environment is another important obstacle to the application of quantum computers. To achieve this, it needs a long coherence time (the time constant of quantum system decay) and very high fidelity. "Increasing the number of bits without reducing the fidelity is a difficult problem in academic circles," Zheng said.
At present, most researchers choose superconducting and semiconductor routes, and engineering and technology are also advancing by leaps and bounds. Developers hope to use advanced semiconductor and integrated circuit technology to promote the development of quantum computers and prepare for the potential integration of quantum computers and classical computers in the future.
From electron tubes to transistors to integrated circuits, with the iteration of materials and processes, the performance of classical computers has been continuously improved. "If measured by the development process of classical computers, quantum computers are now in the early' electron tube era'." Zhang Hui said that quantum computers are still "stupid" and much slower than smartphones and laptops. Quantum computers also have to go through a development process.
"Quantum computing technology is a subversive technology, which is related to the basic computing power of future development."
Zhang Hui believes that the real measure of quantum computing power is who consumes less resources than classical computing when it is used to solve problems.
"At present, quantum computers have not found a more suitable application scenario." Jin believes that a real quantum computer can not only prove that it can do better than a classical computer, but also do more valuable work. If we can only deal with a specific problem, the quantum computer is just an efficient "lumberjack", and it is really useful to know how to make furniture out of wood.
Scientists predict that in the next 10 to 15 years, the scientific community may manipulate 100 qubits, thus realizing "quantum superiority". Guo Guangcan said that in the era of classical information technology, China is a follower and imitator, and quantum computing is an opportunity for China to become an information technology leader in the future. "Quantum computing technology is a subversive technology, which is related to the basic computing power of future development. Whoever gets the quantum computer out first will occupy the commanding heights of the quantum information age. "
The threshold for developing quantum computers is very high. Since the original quantum computing company was established two years ago, the hardware investment alone has exceeded 100 million yuan. But researchers say that quantum computing is like a cave. I don't know if there is any "treasure" in it, but I must have the courage to rush in and see what it looks like.
Five years ago, China Academy of Sciences and Alibaba Group established a joint laboratory to conduct forward-looking research in the field of quantum information science, which was an early layout of quantum computing in China. In recent years, researchers in China have published many influential research results in the field of quantum computing. In Zhang Hui's view, the gap between China and the international "leaders" is not mainly in scientific research, but in engineering technology. Quantum computer is a whole, and we should attach great importance to it except chip, measurement and control, software and algorithm. "Even the weak interference between several wires will affect the overall calculation performance."
Quantum computers and classical computers are not antagonistic and will not completely replace classical computers. "We will never need quantum computers to play computer games." Zhang Hui said that the classic computer has been able to handle most tasks in daily life since its development, and the two should be integrated in the future.
Guo Guangcan believes that it is urgent to master the key core technologies of quantum computers, and it needs real efforts. Only through in-depth and meticulous research and technical precipitation can we make a breakthrough. In particular, we should pay attention to solving engineering problems, so as to seize the development opportunity of quantum computers.
People's Daily (July 20, 2020 19 Edition)