Chen Gen: What information is hidden behind the quantum chip refrigerator?

Text/Chen Gen

Quantum technology is becoming a powerful tool for the country. As a cutting-edge technology that attracts global attention, the 2022 Nobel Prize in Physics was awarded to three scientists for their contributions to quantum information science research.

In fact, quantum technology is not a very new technology, from the establishment of quantum mechanics to the application, it has taken more than a hundred years. Now, quantum technology is moving from the laboratory to the commercial market - according to the Anhui Quantum Computing Engineering Research Center, the first domestic "refrigerator" for preserving quantum chips has been successfully developed and put into use on the first domestic quantum chip production line.

What is the meaning of "quantum chip refrigerator"? Where has the marketization of quantum technology in the mainland come?

Not really a fridge

Of course, the "quantum chip refrigerator" is not a real refrigerator, and even the refrigerator we know is very different.

You know, quantum chips are the core components of quantum computers. Different from the classic integrated circuit chips, integrated circuit chips are mostly based on the first generation of semiconductor material silicon, manufactured into a variety of silicon-based electronic chip products, at present, integrated circuit chips are widely used in smart phones, automobiles, TVs and other terminal fields. However, the performance of integrated circuit chips is also tested by the limits of Moore's Law.

Theoretically, quantum chips can bypass the lithography machine necessary for the manufacture of traditional silicon-based chips, which integrate quantum circuits on the substrate and process and transmit information through quantum collision technology, and almost no lithography machine is used in manufacturing. Test results show that quantum chips are at least a thousand times more performant than electronic chips, and their application range is wider.

But the difficulty is that quantum chips need to go through a complex system production process, such as ambient temperature, cleanliness, noise, vibration, electromagnetic waves, and tiny impurity particles, etc., all of which will affect them.

The reason why quantum chips need refrigerators is precisely because quantum chips have extremely high requirements for the preservation environment. In particular, the superconducting materials in quantum chips are easy to chemically react with oxygen and water molecules in the air, and if quantum chips are not properly stored, they will affect the performance of quantum chips. Just as food is exposed to "oxidative rot" in the air, quantum chips can be unusable because they are "not fresh".

If the quantum chip sample storage environment during or completed tape-out is not up to standard, the superconducting quantum chip will absorb various impurities, and its key components, such as Josephson junctions, superconducting capacitors, etc., will age, resulting in poor qubit frequency consistency, reduced coherence time of quantum chips, and finally deterioration of the performance of quantum chips. Using a self-developed quantum chip high-vacuum storage box to place quantum chips can avoid this problem. Therefore, in order to ensure the normal use of quantum chips, quantum chips must be placed in specific vacuum containers and maintain extremely low temperatures, which is the first "quantum chip refrigerator" in mainland China.

Specifically, the mainland's first "quantum chip refrigerator" is essentially a quantum chip high-vacuum storage box, developed by the Anhui Quantum Computing Engineering Research Center, which can provide a high-vacuum preservation environment for quantum chips, just like a "quantum chip refrigerator". R&D personnel use it to adjust the indoor pressure of storage space, so as to "keep fresh" quantum chips and prevent them from losing their utility. ”

In addition, this quantum chip high-vacuum storage box also has three preservation chambers, a single chamber can be operated independently; At the same time, it is equipped with an intelligent monitoring system, which can monitor the vacuum degree in real time and provide a stable high vacuum environment for the chip preservation process. The R&D personnel have also developed a human-computer interaction functional interface, which can realize the fully automatic operation of the equipment. The "quantum chip refrigerator" has made the future storage of quantum chips settled, and the more important significance of quantum chip refrigerators is to add the last step to the first domestic quantum chip production line.

At the end of January this year, China's first quantum chip production line was announced in Hefei, Anhui Province, and it was Origin Quantum Company based in Hefei, Anhui Province. Specifically, Hefei Origin Quantum is the first domestic quantum computing company, and has created the first domestic quantum chip production line, in this production line, Origin Quantum has created a lossless probe station, laser annealing instrument and other sets of quantum chip industrial mother machine, and the first domestic quantum chip industrial software "Origin Kunyuan" is also from the hand of Origin Quantum.

At present, Origin Quantum has developed a number of Chinese quantum computers and successfully delivered a 24-bit superconducting quantum computer to users, making Mainland the third country in the world with the ability to deliver quantum computers. This production line was put into operation in January 2022, and in the past year, 24 sets of quantum chip production-related process equipment have been introduced successively, 3 sets of self-developed quantum chip special equipment have been incubated, more than 1,500 batches of tape-out products have been produced, and multiple batches of quantum chips and quantum amplifiers have been delivered.

The strategic commanding heights of the scientific and technological revolution

At present, quantum computers are known as the strategic commanding heights of a new round of scientific and technological revolution, which can provide core computing capabilities beyond the limits of classical computers in many key technical fields, and will play an important role in the fields of new material research and development, biomedicine, financial analysis and even artificial intelligence.

Over the past few years, quantum has gone from being a footnote to being at the top of the global security agenda. To date, 17 countries have developed national quantum strategies, and 4 more are in the process of developing them.

According to the Quantum Computing Report, China's investment in quantum research since the mid-80s is estimated at $25 billion. Its top quantum scientist, Pan Jianwei, led the launch of the world's first quantum satellite in 2016 and unveiled what was then-record 56-qubit quantum computers in 2021. China's 14th Five-Year Plan, announced in March 2021, also made mastering quantum technology a policy priority.

In fact, for the continent, quantum technology is also a good opportunity that we cannot miss to overtake in corners. For example, according to the relevant data disclosed by OpenAI, in terms of computing power, GPT-3.5 is trained on Microsoft's Azure AI supercomputing infrastructure (a high-bandwidth cluster composed of V100 GPUs), with a total computing power consumption of about 3640PF-days, that is, if you calculate 10 trillion times per second, you need to compute 3640 days, and you need 7-8 data centers with an investment scale of 3 billion and a computing power of 500P to support operation.

According to Guosheng Securities, based on the NVIDIA DGXA100, 3,798 servers are required, corresponding to 542 cabinets. In order to meet the current consultation volume of tens of millions of ChatGPT users, the initial computing power investment cost is about 759 million US dollars.

In essence, the problem of computing power actually reflects the obstacles encountered by classical computing in the accelerated development of artificial intelligence, especially the bottleneck of computing power. On the one hand, as the chip manufacturing process gets closer and closer to the physical limit, it is becoming more and more difficult to improve the classical computing power; On the other hand, due to the requirements of sustainable development and reduced energy consumption, it is also unrealistic to solve the problem of insufficient classical computing power by increasing the number of data centers. Therefore, improving computing power while reducing energy consumption is a key issue that needs to be solved urgently. In this context, quantum computing has become an important breakthrough to greatly improve computing power.

As an important exploration direction for the leapfrog development of computing power in the future, quantum computing has the potential of parallel computing far beyond classical computing in principle. Classical computers use bits as the unit of information stored, bits use binary, and a bit represents either "0" or "1". But things are completely different in quantum computers, which use qubits as the unit of information, and qubits can mean "0" or "1."

Moreover, because of the superposition property, qubits can also be non-binary in the superposition state, which interacts during processing, that is, "both 1 and 0", which means that quantum computers can superimpose all possible combinations of "0" and "1", so that the "1" and "0" states exist at the same time. It is this property that allows quantum computers to theoretically be several times the capabilities of classical computers in some applications.

It can be said that the biggest feature of quantum computers is their speed. Taking prime factor decomposition as an example, each composite number can be written in the form of multiplying several prime numbers, where each prime number is a factor of this composite number, and expressing a composite number in the form of multiplying the prime factor is called decomposing the prime factor. For example, 6 can be decomposed into two prime numbers, 2 and 3; But if the numbers are large, prime factorization becomes a very complex mathematical problem. In 1994, in order to decompose a large number of 129 bits, researchers used 1600 high-end computers at the same time, and it took 8 months to successfully decompose it; But with a quantum computer, it only takes 1 second to crack.

Once quantum computing is combined with artificial intelligence, it will generate unique value. From the perspective of usability, if quantum computing can truly participate in the field of artificial intelligence, it will not only provide more powerful computing power, surpassing the current time-consuming and laborious construction of ChatGPT models, but also effectively reduce energy consumption and greatly promote sustainable development.

Of course, the road to the marketization of quantum computing is not easy, first of all, the precision of the operation needs to be achieved, that is, the instructions issued need to get a certain result, not a probability. At present, quantum computers cannot achieve the so-called calculation accuracy, and even the same problem, using the same quantum computer to calculate, may eventually have different results each time.

Second, it is necessary to reduce the operating environment of quantum chips. At present, most quantum chips are low-temperature superconducting quantum chips that must operate at about minus 273 degrees. For example, Google's Suzuki quantum computer requires a condition of minus 273.12 degrees. The continent's nine sub-computers require a condition of minus 269.12 degrees for the detection part, and IBM's Osprey quantum computer requires a condition of minus 269.15 degrees. The harsh ultra-low temperature environment has greatly hindered the development speed of quantum chip technology.

Finally, the associated costs of quantum chips need to be reduced. If you want to create an ultra-low temperature environment of minus 273 degrees, you need to cooperate with millions of dollars of refrigeration equipment, which is not only expensive, but also huge. Therefore, quantum chips are still a long way from real commercial use, and it is expected that they will enter the first year of quantum commercial use by 2030, not to mention the use of quantum chips in the terminal consumer market.

But in any case, from the continent's first quantum chip production line to the quantum chip refrigerator, quantum technology is imperative.