2065438+March 2008, Google released the 72-bit quantum processor "Bristlecone" (the quantum system in its chip is arranged like a pine cone), becoming the leader of quantum computers, followed by Intel and IBM with 49 and 50 quantum systems respectively.
In 20 18, Google Quantum AI Lab announced the 72-qubit processor "Bristlecone".
What quantum computers are there on the market? What is the difference?
Google set up a quantum AI lab on 20 13, and hired Martini, a superconducting quantum computer expert at the University of California, Santa Barbara. The team has been working with NASA for a long time with the goal of applying quantum computers to computer science problems such as machine learning.
"MIT Business Review" pointed out that "the agreement between Google and NASA hopes that NASA will analyze the results of quantum circuits running on Google's quantum processor and provide a comparative conclusion between it and the classical simulation scheme, thus supporting Google to verify its own hardware and build a benchmark for quantum hegemony."
The quantum chips or services of companies such as Google and Intel are not open for commercial use at present, while IBM and D-Wave are open for commercial use.
IBM announced the development of the world's first quantum computer with 50 qubits, which was officially unveiled at CES in 20 18. In addition, IBM opened Q System One in the form of cloud computing, and five quantum Bitner were free. At present, it provides up to 20 qubits of computing services, attracting many quantum computer researchers to use it.
Besides these big companies, the most famous small enterprises are D-Wave in Canada and Rigetti in the United States.
D-Wave was founded in 1999, and the world's first commercial quantum computer was launched in 201,and D-Wave One was launched in 128. Lockheed Martin, a well-known American defense industry contractor, also became the first customer.
Because D-Wave entered the field of quantum computer earlier, many enterprises adopted it. For example, Volkswagen uses D-Wave to calculate and simulate the taxi traffic flow in Beijing and find out the best dispatching rules. When Google entered the field of quantum computers, it also bought D-Wave for research.
However, because D-Wave uses quantum annealing technology instead of the orthodox quantum gate technology adopted by IBM, Google and other companies, and D-Wave is only a quantum computer aimed at solving "optimization problems" and cannot solve a wider range of operational problems, the outside world has always held considerable doubts about D-Wave. For example, aronson, a professor at MIT, has publicly questioned D for many times.
In order to prove its technical strength to the outside world, D-Wave published a paper in the scientific magazine Nature, proving that its chip has some quantum characteristics.
In 20 15, Google's research team published a paper, comparing the performance differences between D-Wave 2X quantum computer and single-core traditional computer on several quantum annealing algorithm problems, and the results pointed out that "for some specific problems, the speed of D-Wave is 1 100 million times that of traditional computers." So in a broad sense, D-Wave can also be regarded as a kind of quantum computer.
However, is D-Wave, which takes a special route, better than IBM and Google methods of Quantum Gate School? More applications are needed to prove it.
Rigetti, an American quantum computer startup, was founded on 20 13 by a quantum computing physicist from IBM. In addition to quantum chips, it also launched a cloud computing service for quantum computing.
Fujitsu with Quantum-like Operation
Inspired by quantum computer technology, Fujitsu, the largest IT service provider in Japan, introduced DAU (digital annealing Unit) and server products using digital annealing technology by simulating quantum annealing calculation method.
Because Fujitsu uses "quasi-quantum computing", Liu Meijun, an industrial analyst at the Institute of International Gynecology and Obstetrics of the Institute of Technology, pointed out that "if it is to be strictly calculated, its technology does not take advantage of quantum entanglement and superposition, or take advantage of traditional chip circuits to conduct parallel computing, which is not a real quantum computer."
In other words, although Fujitsu's product name is related to quantum computers, it is not a product of quantum computers, but can only be counted as supercomputers in traditional computers.
At present, the most mainstream school of making quantum chips is to use "superconducting materials". The advantage of superconducting materials lies in the high speed of quantum system, which is easy to produce multiple quantum systems to realize quantum entanglement, thus attracting the research and development of technology companies such as Google and IBM.
In addition to superconductor materials, semiconductor materials can also be used to make quantum computer chips. Although superconductor materials have attracted much attention, the technological development of superconductors in the global manufacturing industry is not as mature as that of semiconductors, and the manufacturing process of semiconductors is similar to that of existing mainstream chips, which is why Intel supports the Institute of Semiconductor Materials Technology very much, which is also close to the core competence of the semiconductor industry in Taiwan Province Province.
However, these technical factions have their own advantages and disadvantages, which does not mean that one technical scheme is better than the other. The final development is still hard to say, and it has not yet reached the stage of major breakthrough.
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As for the number of quantum systems, Mou Zhongyu, a professor of physics at Qingda University, stressed, "Although the number of quantum systems is very important, the quality is more important. With the present technology, there must be a debugging mechanism to reduce the error rate and improve the accuracy. So in practice, a quantum system needs three to five or even hundreds of quantum systems. Therefore, the 50 qubits of Quantum Hegemony may need thousands of qubits in actual operation to improve the overall quality of qubits. "
In addition, quantum is vulnerable to external interference such as electromagnetic waves and thermal radiation, so technically, it is necessary to keep quantum entangled in a stable state and complete the measurement and operation time, which is called coherence time. At present, the best performance in the industry is 10 minus cubic seconds. If the coherence time is too short, it is impossible to complete meaningful calculation and it is difficult to improve the accuracy.
It can be seen that quantum computer technology is still in a very early stage, and various companies use different technologies to develop quantum computers. Therefore, at this stage, when enterprises launch quantum chips, it is impossible to compare the technological progress of various companies fairly and objectively, and we must look at this new technology with more suspicion.