Exploring quantum supremacy: Towards a supercomputing revolution

Quantum supremacy refers to the fact that quantum computers have achieved advantages over traditional classical computers on certain specific problems, demonstrating their powerful computing capabilities in an obvious and significant way. It is a milestone event in the field of quantum computing, indicating that quantum computers can outperform traditional computers in certain situations and gain advantages on corresponding problems.

Let's use an analogy to illustrate: suppose you and your friend both have a very complex math problem to solve. You use traditional paper and pen (similar to a classical computer) to solve the problem, while your friend uses a brand new magic pen (similar to a quantum computer). This math problem is very difficult for you and may take a long time to get the answer. But your friend easily finds the answer with the magic pen, and it is very fast, only taking a few seconds.

In this example, you represent the traditional computer, and your friend uses the magic pen to represent the quantum computer. Quantum supremacy means that for certain specific problems, quantum computers can quickly find answers, while traditional computers may take years, thousands of years, or even longer to complete the same task.

Why are quantum computers so fast?

Imagine that we have to get out of a complicated maze. A traditional computer is like a diligent little man, constantly making choices at forks in the road, exploring and moving forward step by step. Once it goes wrong, it has to go back and start over again, wasting a lot of time and energy. A supercomputer is also a little man, but it moves faster and more efficiently. Although it can find the exit faster, it still explores step by step in essence.

Quantum computers are completely different. Their little man is a magical master of clones, just like Sun Wukong can create many little monkeys. Whenever it encounters a fork in the road, it does not need to make a choice. It can create multiple selves at the same time, and each clone goes to a different fork in the road. In this way, quantum computers can perform multiple parallel calculations at the same time, resulting in an exponential increase in efficiency.

To explain it in the language of elementary school mathematics, suppose we want to calculate a*b*c*d*e*f, a traditional computer needs to calculate a*b in sequence, then multiply the result by c, then multiply by d, and so on, which is a step-by-step approach. However, a quantum computer can calculate a*b, c*d, and e*f at the same time, greatly shortening the calculation time. This is why quantum computers are far ahead of traditional computers in certain specific computing fields, and their speed is incredibly fast.

It is worth noting that quantum supremacy does not mean that quantum computers have completely surpassed classical computers. It only means that quantum computers have advantages in specific problems. For example, my country's quantum computer "Jiuzhang" was designed to "solve Gaussian boson sampling". It is very fast in solving such special problems, but it may not be as fast as our computers and mobile phones in other computing tasks. It can be said that all quantum computers are still special-purpose computers and cannot solve general problems like classical computers.

In fact, a more accurate name for quantum hegemony is "quantum superiority". This term emphasizes the advantages of quantum computers in specific tasks rather than absolute hegemony. This name is more in line with scientific objectivity and more accurately reflects the actual capabilities and application scope of quantum computers.

Source: Chongqing Radio Science Popularization Experience Center

Audit expert: Yang Wenyan

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