Nine chapters have come out. Do you know what a quantum computer is?

  On December 4th, Science magazine announced that the "Nine Chapters" of the quantum computer built by China’s research team has achieved a fast solution to the Bose sampling problem, and its calculation speed is faster than the fastest supercomputer at present.One hundred trillion times!

Quantum computer screens the whole network

Netizens are proud and happy about it.

But as soon as I opened the article,

Most friends can only leave a question mark after reading it:

"I know every word, but … …”

"Why is quantum computer so fast?"

Don’t worry!

Here is a "Little White" friendly explanation book.

Let’s put it in layman’s terms.

(This article does not involve any theoretical formula or academic discussion … …

Because Xiaobian is not professional! )

Is quantum computer a computer?

  First of all, what is a quantum computer in one sentence:

  Quantum computer is a kind ofA computer using quantum mechanicsIt can perform some specific calculations more efficiently than ordinary computers.

  So, quantum computer is a kind of computer, but it is not simple."Advanced Edition" computer.And what we now understand as "computer"There is a big difference— — The calculation forms of the two are different.

  For example:

  If the classic computer iscandle, quantum computer islight bulb / third wheelBoth of them are for lighting, but the lighting methods are different and the lighting range is also different. Even if you keep improving candles, you can’t make a light bulb.

  At present, quantum computers use physical systems such as atoms, ions and photons.Different types of quantum computers use different particles.This time, the "Nine Chapters" use photons.

  200 seconds is just a short moment, and 600 million years has already passed.

  How did the "Nine Chapters" quantum computer achieve the "ultra-fast" computing speed through quantum computing?

How does a quantum computer calculate "ultrafast"?

  quantum computer"huge storage capacity"

  First of all, let’s take a look at the storage mode of classical computers and quantum computers ↓

Classic computer

  With a series of0 and 1To store information. Each unit in the series of 0 and 1 is called a bit, and one bit can be set as0 or 1.

quantum computer

  For quantum computersQuantum bitTo store information. Each qubit can not only be set to1 or 0, and can also be set to.1 and 0.

  It can be simply understood that quantum computers store more information per unit.

  What exactly does this mean?

  For example:

  Please think of a number between 1 and 10 and express it with one hand. One hand at a time.Only one number can be expressed.

  This is the fundamental law of storing data in classical computers. It’s just that the computer is faster than our fingers, but one bit of it can only store one binary number.

  However, if you switch to a quantum computer, the way to express numbers will be immediatelyBe subverted.

  For another example, one hand can express 10 numbers. But before the hand reaches out, which number will it represent,Is uncertain.

  This is the storage unit of quantum computer — —Quantum bits,The storage mode of. It stores not specific data, but all possible data.Probability of occurrence.

  Hands are uncertain until they reach out. But qubits take all the numbers that can be expressed with this hand, all of themoverlayTogether. You only use one hand to store 10 different numbers, and the probability of each number appearing is 10%.

  The number that one hand can express is very limited, and it is not a magical thing to store 10 numbers at the same time. But it keeps expanding, and 10 hands and 100 hands can all be used.Superimposed storageIn qubits, this is the power of qubits.

  Quantum computers can therefore carry more content at the same time. Ordinary computer units can only process one bit at a time; Quantum computers can process one "qubit" at a time, thus greatly improving the processing speed.

  The quantum world is essentially parallel.

  Quantum computer not only has powerful storage capacity, but also has powerful parallel computing capacity. Just like turning on a light in a room, light can pass through all the cracks in the wall in an instant. It is this principle that quantum computers can perform high-speed parallel quantum calculations.

  For example:

  Suppose there is a black box with 1000 wire ends sticking out on the left and 1000 wire ends sticking out on the right, but in fact,Only one wire is connected.Dear, excuse me, how do you find this connected wire?

  The answer needs to be tried 1000×1000 times, that is, to1 million timesTo find the answer.

  But it’s much easier to solve this problem with a quantum computer.

The actual operation process of quantum computer

  As we said just now, the storage of qubits is the superposition of all possible numbers. Then from 1 to 1000, it is actually just a group of qubits. In other words, with only one calculation, the quantum computer takes all the possibilities into account at the same time. It can find the connected wire once. Through parallel computing, the efficiency is improved by 1 million times.

  How to calculate this quantum computer, do you see (mei) understand (kan) (dong)?

Why are the "Nine Chapters" so important?

  The appearance of "Nine Chapters" is another leap in the field of quantum science and technology in China, and its significance is multifaceted.

  The first is in the fields of computer, IT and mathematics.If "the superiority of quantum computing" is realized, the computing power on a specific problem far exceeds that of the most powerful traditional computer. In addition, it can also establish quantum communication networks and quantum internet through quantum computers.

  Secondly, in terms of practicality.Quantum computers have a broad space and scope, such as password decoding, big data optimization, material design, etc., which can all be supported by quantum computers, thus solving major national economy and people’s livelihood issues and generating great economic value.As predicted by some scientists, quantum computers will be widely used, and even everyone can use them.

  At the same time, the development of quantum computers,Will bless artificial intelligenceThereby reducing the mistakes in AI application and creating an intelligent system that allows early diagnosis of problems.

  It is worth mentioning that it alsoClosely related to drug research and development.. If quantum computer is used, as long as its calculation speed is 100~1000 times faster than that of classical computer, it is possible to improve the efficiency of screening prodrug molecules to more than 90% and reduce the cost. However, whether the truly effective drug molecules can be obtained depends on the later biological experiments.

  In addition, the fast operation of quantum computers also includesOrdinary but widely used. For example, how to choose the most efficient route for delivery trucks can rely on the help of quantum computers. This is by no means "overqualified".

How far is quantum computing from practicality?

  For the research of quantum computer, international peers in this field have recognized that there are three stages of development:

  The first stage,For some high-complexity specific problems that supercomputers can’t solve, efficient solutions are realized, and in computational science."that superiority of quantum compute"A milestone.

  The second stage,Development of coherent manipulation of hundreds of qubitsQuantum simulatorIt is used to solve some problems with great practical value that supercomputers can’t do (such as quantum chemistry, new material design, optimization algorithm, etc.).

  The third stage,Develop a programmable universalQuantum computing prototype.

  Classical computers have developed from special-purpose computers to general-purpose computers for decades, and now quantum computers are still in the earliest era of special-purpose computers. Even the fastest "Nine Chapters" only crossed the first stage. However, it is undeniable that the appearance of "Nine Chapters" is a great encouragement, and the future can be expected.