Subverting thinking can understand quantum mechanics.

Interstellar travel, time travel, spiritual transportation ... countless literary and film works show us the future of human science fiction. These are not the random imagination of the creators, and they all have a basic theoretical basis-quantum mechanics. Quantum mechanics is the frontier of physics research today. But for ordinary people, quantum mechanics seems unfathomable.

On May 3rd, the world's first quantum computer, which surpassed the early classical computers, was born in China, and quantum mechanics made a major breakthrough in practical application.

So, what does quantum mechanics say? What was its past life like?

With awe of science, I hope to simplify the complex and write down the development of quantum mechanics and how ordinary people understand it in the most simple and understandable language, and unveil the mystery of quantum mechanics with everyone.

1、

The earth is bathed in sunshine and everything grows.

What is "light"? But for thousands of years, mankind has benefited from the gift of light. But I don't know what it is, I can only make some guesses.

Human ignorance of light did not begin to change until 1655. British naturalist Hooke put forward the wave theory of light. He thinks that light is a wave, similar to water waves. Huygens, a Dutchman, published The Theory of Light, which developed this theory.

Their opponent is Newton. He put forward the theory of light particles, which holds that light is a tiny particle and follows the law of motion.

These two schools of thought are at loggerheads, but both have defects.

According to Newton, light is a tiny particle. He reasonably explained the linear propagation and reflection characteristics of light. Newton's explanation of refraction and diffraction of light is not satisfactory.

Huygens and others think that light is a wave. Then there needs to be a propagation medium, such as sound waves passing through the air and water waves passing through the water. But there is no substance in a vacuum. How does light spread?

They say that all spaces have an invisible substance called "ether", through which light travels. However, if the "ether" really exists, then the earth rotates at a speed of 30 kilometers per second, and we should be able to feel the "ether wind" blowing head on. A large number of experiments have proved that there is no "ether wind" blowing.

Because of Newton's unparalleled academic position, his particle theory occupies a dominant position. In the following 100 years, no one dared to challenge, and Huygens' theory was gradually forgotten.

180 1 year, Thomas Jin Yang conducted a famous experiment-"double-slit experiment".

The experiment is simple.

A beam of light is projected on a background board, and another board with two adjacent notches is placed in front of it.

If light is a particle, the result of the experiment should be that two narrow beams of light are projected on the background plate. But the experimental results greatly surprised people.

There are many projections on the background board. This is a disaster for light particles.

Because this phenomenon is the expression of waves.

When we observe water waves, we will find that where two water waves overlap, the water waves will be higher when the peaks and troughs meet, and the water waves will cancel each other when the peaks and troughs meet. This common phenomenon is called interference.

Only the waves will interfere.

The black and white stripes on the experimental background board prove the interference phenomenon of light, thus proving that light is a wave. The double-slit experiment completely shook the rule of light particle theory.

In the following 50 years, the theory of light fluctuation has been further developed. By the middle of19th century, it began to dominate the scientific trend of thought. It is recognized that light is a wave, not a particle.

2、

With the great development of physics in the19th century, scientists think that human's mastery of physics has become perfect, and then they study it, but they just add a few numbers after the decimal point of the known results.

Planck's teacher in Germany also advised him not to study pure theoretical physics. The advice of two tutors didn't convince him.

/kloc-the last day of the 0/9th century, 1899, 12, 3 1, physicist Kelvin delivered a speech to welcome the new century: "The physics building was built in the 0/9th century, and the task of future physicists is to decorate and improve this building."

Planck was very unhappy about it. He is having a headache for a calculation problem that has not been solved for six years.

The two formulas summarized by physicists at that time could not accurately calculate the radiation emitted by objects. One can calculate the result in the long-wave part of radiation, and the other formula can be correct in the short-wave part of radiation, but once it reaches the opposite wave band, the answer is a thousand miles away.

Planck couldn't understand the meaning, and his research was in a long-term dilemma.

Planck, who "put all his eggs in one basket", thought, otherwise, first, force the two formulas into a formula that satisfies all bands, and then infer backwards to see what the result is.

In this way, if a combination formula is to be established, when an object emits radiation, the energy can't be continuous, but it changes by leaps and bounds in tiny integer multiples, that is, the energy changes one by one.

190 1 year, and he published the calculation results. In his paper, he named this energy "quantum".

Other scientists verified Planck's correctness and quantum mechanics was born. Planck became the "father of quantum".

3、

After 1880, Edison's improved light bulb began to spread widely. The utilization of light by human beings has reached an unprecedented height.

Hertz, a German, found that when ultraviolet rays are used to irradiate metal, electrons in the metal will be excited to form an electric current. Light generates electricity.

Hertz called it "photoelectric effect", but he could not explain it.

1905 is called "Einstein miracle year" in the field of physics. During this year, Einstein published five epoch-making important papers. One of the papers on "photoelectric effect" directly won Einstein the Nobel Prize.

In his paper, Einstein once again mentioned the particle theory of light. According to the theory of light particles and the concept of quantum, light should be composed of discrete tiny particles, which is called "light quantum" for short.

When a photon hits a sensitive metal, its energy is absorbed by electrons in the metal. The kinetic energy of electrons increases, which overcomes the attraction of the nucleus and flies out of the metal surface, becoming photoelectrons and forming photocurrent.

Einstein's explanation of photoelectric effect shocked the physics circle which has generally recognized the theory of light fluctuation.

A series of experiments verified Einstein's correctness, and people began to realize that light has both fluctuation and particle characteristics. As for what light is, this debate, which lasted for nearly 300 years, finally ended with the emergence of a magical concept-the wave-particle duality of light.

Scientists have gained a new idea that a substance can have two completely different properties at the same time. Wave-particle duality is like a key, which opens the door to the microscopic world. Physicists have further discovered that elementary particles have wave-particle duality.

After decades of unremitting research, the contradiction between quantum mechanics and the classical physical theory that has been used for nearly 300 years has become increasingly obvious.

This happens because the quantum phenomenon discovered by scientists has never appeared in the macro world. The opposition between quantum mechanics and classical mechanics is the epitome of the opposition between micro-world and macro-world.

Shouldn't the same world have the same theory?

Einstein began to question. Quantum mechanics is so mysterious that the concept put forward is really puzzling. Einstein was one of the founders of quantum physics, but at this time he stood up and profoundly denied some basic concepts and completeness of quantum mechanics itself.

Quantum physicists disagree with him. Undoubtedly, the emerging quantum mechanics has made great achievements. Various academic journals have a strong smell of gunpowder. It seems that if these scientists meet, they will have the fierce eloquence of Mars hitting the earth. Soon, such a meeting really came.

4、

"Superficially strongest" physicist debate

Belgium, 1927. The famous fifth suwei conference.

This is the greatest gathering in the history of physics. For example, Huashan talks about swords, and all the top experts in the rivers and lakes are present, all of which are flag figures of various branches of physics. Of the 29 participants in the photo, 17 have won the Nobel Prize, which is called the "all-star" event in physics.

Einstein sat in the middle of the photo, which shows his position in the academic circle at that time. Taking causality as a weapon, he analyzed the present situation of quantum mechanics and pointed out that the research of quantum mechanics was not satisfactory.

The so-called causality theory means that everything comes into being and develops with cause and effect. This is a seamless truth.

Einstein's supporters include Schrodinger and De Broglie.

His opponents are numerous, and they have a unified name-Copenhagen School. At the helm was Bohr, who laid an important theoretical foundation for quantum mechanics. It is particularly worth mentioning that Bohr once visited China, and he put China's Tai Chi map in his family emblem. Bohr thinks Tai Chi perfectly explains his complementary principle. Just like the wave-particle duality of light, the properties of waves and particles are complementary.

Bohr led a group of talented young people in their thirties. Born, Heisenberg, Pauli and Dirac are the main members of this school. Their explanation of quantum mechanics is called "orthodox explanation" of quantum mechanics.

The argument of Copenhagen School is based on computational probability theory. In the quantum world, the result is often not clear, just a probability.

Let's illustrate the "quantum tunneling effect".

It is generally believed that electrons cannot pass through the insulating layer sandwiched between two metals. But the Copenhagen school says that it is possible for electrons to pass through the insulating layer. After calculation, the numerical value of probability can be obtained. This is the "quantum tunnel". If put into the macro world, can people walk through walls? According to quantum tunneling, macroscopic objects can also have tunneling effect. It is also possible for a person to go through the wall, but it is actually impossible to require all the microscopic particles that make up this person to go through the wall at the same time. But in probability, people can walk through walls.

Einstein sneered at such a probability theory. The existence of probability is only an incomplete proof of quantum mechanics theory. Quantum mechanics has not yet found a complete theory to describe the micro and macro worlds.

"God can't roll dice," Einstein said.

"Einstein, don't tell God what to do!" Bohr hit back.

5、

Einstein didn't win the prize at the 5th Solvay Conference, and even failed. He is unwilling. In the sixth session three years later, he made a comeback.

Einstein summed up his experience, gave up the discussion of specific cases and pointed his finger at the theoretical basis of Copenhagen School-"uncertainty principle".

Let's briefly introduce this principle. In order to understand the inside of atoms intuitively, people will draw such a picture.

Electrons revolve around the nucleus, which looks like planets revolve around the sun.

But this is wrong. The orbit does not exist. In fact, the inside of the atom looks more like this.

Like clouds, scientists call them "electronic clouds". This looks like a dense cloud, in which there are actually only a few electrons, even 1.

Clouds appear because electrons move near the speed of light in a narrow atomic space, and only one cloud can be seen.

The uncertainty principle says that inside an atom, the movement of electrons is irregular. When we know the position of electrons, it is impossible to know their speed. The position and velocity cannot be known at the same time, which is contrary to the classical physics that describes the macro world. For example, we can calculate the speed and position of the earth around the sun at any time.

Einstein believes that there is no such uncertainty principle only because we lack the means of observation and reasonable formula.

Having breakfast in a hotel every day, Einstein described a thinking experiment when scientists were in a meeting. From this experiment, he thought that the contradiction explained by Copenhagen School could be seen clearly.

Bohr explained these ideal experiments in the evening, and he would analyze them for Einstein at dinner.

Einstein could not refute these analyses, but in his heart, he was unconvinced.

At the sixth Suwei conference, Einstein ended in failure again.

As the Second World War was imminent, Einstein was persecuted by the German Nazis and fled to the United States. He did not attend the seventh Solvi Conference three years later.

Solvey's conference on quantum mechanics is over, but the debate about quantum mechanics continues.

6、

From 65438 to 0935, Einstein and his supporters launched a general attack on Copenhagen School.

Einstein questioned quantum entanglement.

Quantum entanglement is another wonderful phenomenon in the quantum world. Scientists have found that two and only two entangled quanta can be produced in the same special reaction. These two quanta act on one of them like twins, and the other will make the same change at the same time. For example, a pair of entangled electrons, if their entanglement mode is reverse entanglement, one rotates in the forward direction, then the other must rotate in the reverse direction. Suppose you change the front electron to reverse, then the other electron will also change to forward. Moreover, no matter how far these two electrons gather, even at the two ends of the galaxy, they can't be prevented from changing at the same time.

How are they connected? This connection speed even reached ten times the speed of light. This is not scientific. Because according to the theory of relativity, the speed of light cannot be surpassed. Einstein called this ghostly connection "ghost effect".

It is true that until today, we have no conclusive evidence to find substances that can exceed the speed of light. So the Copenhagen school told Einstein that the world is like this.

Schrodinger, Einstein's main supporter, even proposed an experiment that seemed like a nightmare to Copenhagen school-"Schrodinger's cat".

Since the theory of quantum mechanics is to explain the microscopic state, how can it be combined with the macroscopic world? Schrodinger assumes that a nucleus is placed in a box. The nucleus is a quantum concept, which will spontaneously decay in an uncertain time. No one can predict the exact time of decay. A mechanical device is designed in the box. When the nucleus decays, a hammer will be connected to break the poison gas bottle that can poison cats. Put a cat in the box, and then cover the box. Will it be a live cat or a dead cat in the box after a period of time?

According to the theory of Copenhagen school, observing behavior will change the state of material change. Well, what about observation?

In this regard, the Copenhagen school can only swallow the bitter water and admit that cats are in a mixed state of half death.

The debate between Bohr and Einstein is also the debate between quantum mechanics and classical mechanics. Although the debate is still inconclusive, it has promoted the development and perfection of quantum mechanics.

This debate widely spread the views of Copenhagen School.

Scientists did not stop, they cleverly bypassed the study of who is right and who is wrong, but chose to be loyal to the experimental conclusions and calculation results. When asked about the principle of quantum mechanics, most physicists will say "shut up and do the calculation".

Bohr said, "Everything we call true is made up of things we can't call true." Quantum mechanics is full of strange theories, but all experiments and calculations have proved that it is correct. The principle is unknown; Einstein was proved wrong.

According to the equations of quantum mechanics, people have designed switches that can control tiny current, which are applied in most fields of electronic industry such as lasers, transistors and integrated circuits. It can be said that if quantum mechanics is not established, then our computers, mobile phones, cameras and other electronic components will fail. Without the world of quantum mechanics, we can only go back to age of steam.

7、

The above is a simple development process of quantum mechanics. In recent years, the word quantum mechanics appears more and more frequently. How can we ordinary people easily understand quantum mechanics? If we can break a few stereotypes, we can also enter the wonderful world of quantum mechanics.

One of subversive thinking, quantization is everywhere.

Judging from the name of quantum, many people think it is a tiny particle when they see it called "child". When understanding quantum, please ignore the word "sub" behind and look at the word "quantity" in front. Quantum means "how much" in Latin, which stands for "a certain amount of a certain substance".

Although quantum mechanics studies elementary particles, quantization is an attribute of the universe. From the planet to the cell, the final decomposition can be quantized. Even in human thinking, science has proved that our consciousness is not continuous, and there is a slight disconnection every 0.042 seconds. Then our consciousness can be regarded as a quantized consciousness in 0.042 seconds.

The macro world we live in is made up of the micro world, and there is no clear boundary between them. Even our human body is made up of tiny atoms. According to the duality of wave and particle, if I tell you that people are also made up of waves, then there is no need to be surprised. This has been answered in de Broglie's "material wave" theory.

In addition, abstraction into space can also be quantized. The quantization of space produces wormholes. The concept of wormhole means that as long as we have enough energy, we can open the gap in unit space. With such wormholes, we can travel in time and transfer in space. This is not science fiction, at least it is feasible in mathematical calculation. Wormhole, also called "Einstein-Rosen Bridge", was calculated by Einstein and Rosen when they were studying the equation of gravitational field.

For example, the mystery of Tai Chi, macro and micro blend with each other, rather than opposing. Classical physics to explain the macro world and quantum mechanics to explain the micro world are still extremely incompatible and have not reached an agreement, but some scientists have begun to unify them through experiments. From this, more wonderful and great theories may be produced.

Subversive thinking II: There is no unique truth, even in science.

Newton discovered gravity when the apple hit his head. Today, we know that throwing apples can even throw them out of the earth as long as there is enough energy. This is unimaginable to ancient people.

Truth is relative when there is no end to cognition.

Assuming that the world is just a plane and we are all two-dimensional plane people, then we can't even understand the principle that two footprints appear on the ground of a three-dimensional world. Fortunately, we are three-dimensional and know that there is a complete person on the footprint. What is the "ghost effect" of long-distance quantum entanglement? At present, scientists have different explanations. Some people think that the speed of light is not the limit speed, and the superluminal conduction produces a "ghost effect". However, some scientists believe that the universe itself is a 1 1 dimensional space, and the "ghost effect" is caused by the compressed invisible dimension in the space.

Although the principle is still unclear, China has launched a quantum communication satellite in August last year, taking advantage of quantum entanglement to lead the world.

Quantum mechanics is permeating all fields of science. For example, biologists have even proved that our sense of smell is not generated by molecules that we usually think smell things, but like our ears, we "hear" the fluctuations of subatomic particles in things to distinguish them. Quantum biology is subverting traditional biology.

Scientific research continues, and what is certain is that the world we see is not all of it.

The third kind of subversive thinking: without absolute existence, probability is the true face.

If you are in Beijing, where are you in Beijing for me? The explanation of quantum mechanics is that you are anywhere in Beijing. Just as we want to know the position of an electron in an atom, the electron exists in the whole atomic space in the form of waves, and it will not appear at a specific point until you observe it. Similarly, when I have not observed or been told, you are like an electron, and there is a probability of existence in any corner of Beijing.

Quantum mechanics can't explain this logic accurately at present. They say this is the real world.

The significance of this probability is more practical in the current quantum computing.

As we all know, the mathematical basis of modern computers is binary. In computer binary, a unit of information is called a bit. One bit can be 0 or 1. If I enter two digits 0 1, it will still be 0 1 after transmission. Quantum bits are different. I input two smallest units of quantum bits, both of which may be 0 or 1, and the probability is equal. At this time, the output result is no longer a single message, but four possibilities, 00, 0 1,1,1. Quantum computing gives us four alternative and uncertain answers with equal probability. This can be simply considered as the principle of quantum computing.

2 qubit information, the answer is 2 to the second power; Three qubits are the third power of two; ..... 20 qubits, which is 2 to the 20th power, that is, 1 million or more.

Quantum computing will increase geometrically with the increase of quantum bits. For example, we want to find the one we want from the information of 654.38+0 million bits. Quantum computers don't search one by one like classical computers, but search 654.38+00000 answers at the same time. As long as the conditions are set, the computer can find this bit information in one second.

This is the computing power of quantum computer announced by China on May 3rd. Because scientists in China have realized the quantum calculation of entangled state 10 pairs, 10 pairs -20 quanta, that is, 20 qubits in calculation.

In order to judge whether quantum computing is awesome, there are three index nodes in academic circles: the first step is to surpass the early classical computers in computing power, then surpass the personal computers we use, and finally surpass the supercomputers.

Scientists in China took the lead in completing the most difficult first step in the world.

The quantum computer is so close to us.

The theory of quantum mechanics has a history of 1 17 years since the birth of the word quantum. Quantum mechanics has subverted our lives. With the in-depth study of quantum mechanics, practical quantum products will eventually usher in a blowout day.

Bohr said: "If someone is not shocked by quantum theory, then he doesn't understand it at all."

Our ignorance of quantum is just like our ignorance of light more than 300 years ago. In the process of exploring the secrets of the quantum world, the flower of wisdom is also quietly blooming.

Perhaps, one day in the future, mankind will fully understand the quantum world and find that quantum mechanics, an ultra-modern science, is an ancient fact of life.