What exactly is the "angel particle" discovered by China scientist Zhang Shousheng?

First of all, the scientific name of angel particles is "Chiral Mayorana Fermion". However, unlike ordinary electrons or protons, the "angel particles" discovered by China scientist Zhang Shousheng and other experimental groups are not real particles in essence, but quasi-particles appearing in condensed matter physics. It's a bit like what? If particles are really "stocks", then quasi-particles are a bit like "stock index futures"-an abstract financial derivative.

So, why did Zhang Shousheng discover the chiral Mayorana fermion named "angel particle" this time? Let me analyze and interpret this for you. It may be wrong. After all, I am not Mr. Zhang Shousheng. I can only guess and analyze his ideas:

First of all, this chiral Mayorana fermion is special. It can be seen from Dirac equation of particle physics that there are both positive particles and antiparticles in general particles. For example, electrons and positrons are not the same kind of particles, but two kinds of particles-just like our palms, there are left and right hands, and the left hand is not equal to the right hand. But the chiral Mayorana fermion discovered this time is characterized by that the positive particle is antiparticle, that is to say, this particle is like an alien with only one hand-left hand or right hand? Therefore, according to the thinking habits of westerners, the metaphor of "angel and devil" is generally used, so now the angel and devil are combined in the same particle, so it is named angel particle.

Secondly, because an important elementary particle, the Higgs particle, was discovered in 20 12, it was called the God particle. Now, perhaps in order to correspond to God and highlight the importance of his discovery, it is named "angel particle".

In addition, Zhang Shousheng is a famous angel investor, and Danhua Capital is responsible for it. The word angel should be the most kind to him.

Finally, it may be because physicist majorana is an angel with broken wings-he died early and disappeared when he was young, which became a mystery in physics. This particle was originally called "Chiral Mayorana Fermion".

Positive and negative, yin and yang, good and evil ... the world seems to be full of opposites. British physicist paul dirac predicted in 1928 that every elementary particle has a corresponding antiparticle. A few years later, scientists found the antiparticle positron of electrons in cosmic rays, which verified this prediction. 1937, Italian physicist ettore majorana predicted that there may be a special kind of particles in nature, and their antiparticles are themselves. This hermaphrodite particle is called the Mayorana fermion.

However, the evidence of the existence of the Mayorana fermion has not been found. Together with neutrinos and Higgs boson, it has become a particle that has been predicted for a long time but cannot be verified for a long time. Now, the Zhang Shousheng team has finally found the evidence of its existence.

In the process of searching for "angel particles", the theoretical team led by Zhang Shousheng predicted what kind of experimental platform can be used to find Mayorana fermions and what kind of experimental signals can be used as evidence; The experimental team led by He Qinglin and Wang Kanglong of UCLA and Xia Jing of Irvine University worked closely with the theoretical team, and found the most basic Mayorana fermion in the experiment, which is called chiral Mayorana fermion. Fudan University in China and Shanghai University of Science and Technology also contributed to the experiment.

According to the prediction of the theoretical team, the researchers built a hybrid device to place ordinary superconductor films on quantum anomalous Hall effect films (that is, magnetic topological insulators). After applying a low-intensity external magnetic field, the researchers measured a semi-integer quantum platform, which became the experimental evidence for the existence of chiral Mayorana fermions.

Zhang Shousheng explained that in previous quantum anomalous Hall effect experiments, with the adjustment of external magnetic field, an integer quantum platform would appear. This is the usual particle behavior. Mayorana fermion has no antiparticle, which is equivalent to a semi-traditional particle. Therefore, when ordinary superconductors are placed on quantum anomalous Hall effect films, a semi-integer quantum platform will appear outside the usual integer quantum platform.

The research team led by four China scientists finally found the androgynous "angel particle"-Mayorana Fermion, thus ending the 80-year search for this mysterious particle by the international physics community.

Related papers were published in the journal Science published today. This achievement was jointly completed by Wang Kanglong of UCLA, Professor Zhang Shousheng of Stanford University and Kou Xufeng of Shanghai University of Science and Technology. The authors of the communication are Lin Qing, Kou Xufeng, Zhang Shousheng and Wang Kanglong, all of whom are scientists in China.

Today, Science magazine published a paper by Professor Zhang Shousheng and his collaborators. This work embodies a good combination of theory and experiment. Teacher Zhang is the theoretical person in charge of this work. According to teacher Zhang's theoretical scheme, the experimental group found that the conductivity shows that the collective behavior of electrons is the behavior of Mayorana Fermion on the one-dimensional interface between two-dimensional abnormal quantum Hall effect insulator (i.e. magnetic topological insulator) and superconductor.

In the final analysis, this is the behavior of electrons in solid materials. Under the solid environment (complex potential energy formed by external conditions such as nuclear array and magnetic field) and their interaction, a large number of electrons can be simply described as "quasi-particles", that is to say, a large number of electrons behave here as if they excited a large number of "quasi-particles" on the basis of the lowest energy state. In order to emphasize that these "quasi-particles" were born at a new level, and their environment is similar to the basic particles in our universe, we can also call them "evolutionary particles".

Now, Teacher Zhang and his collaborators have discovered an evocative particle similar to the Mayorana fermion in a specific solid environment. The so-called "discovery" means that the conductive behavior must be explained by the Mayorana fermion. The Mayorana fermion they found is on the one-dimensional boundary between insulator and superconductor in the two-dimensional magnetic topology, which makes it chiral, that is, it runs in one direction.

Fermions are such quantum particles. In the same system, the state of the same fermion (considering all indicators) must be different. Electrons (whether in free space or in solid materials) are fermions. Mayorana fermion is a special kind of fermion, that is, its antiparticle is itself. Antiparticles can be defined as follows: producing an antiparticle is equivalent to destroying a particle with many properties (momentum, angular momentum, charge, etc.). ) in contrast. And vice versa, positive and negative particles are relative. The Mayorana fermion has not been found in the free space of the universe. Neutrinos may or may not be, and the answer is unknown.

Teacher Zhang called Mayorana Fermi an angel particle, because he noticed that in the novel Angels and Demons, the positive and negative particles annihilated and the world disappeared, while Mayorana Fermi could be compared to an angel without a devil.

According to the definition of particle physics, matter consists of two basic particles, fermions and bosons. Fermions are the raw materials of matter (such as leptons, quarks and electrons in neutrinos that make up protons and neutrons). Bosons are particles that transfer force (photons, mesons, gluons, W and Z bosons).

Majorana fermion, on the list of mysterious particles, is a kind of fermion. Its uniqueness lies in that it is a particle without antiparticle, or antiparticle is itself.

The discovery of chiral Majorana fermion successfully ended the 80-year exploration of this mysterious particle. Compared with the annihilation and explosion of positive and negative particles described in Dan Brown's novel Angels and Demons, Zhang Shousheng proposed that the newly discovered chiral Majorana fermion should be called angel particles: we found a perfect world where there are only angels but no demons.

The significance lies in:

The discovery of Fermion in Mayorana will challenge the understanding of the existing world from the philosophical level, that is, the world is not completely opposite, yin does not necessarily have yang, and angels do not necessarily have demons. In addition, this discovery has more practical significance-it will be possible to realize topological quantum computing in solid state.

In Zhang Shousheng's view, the discovery of angel particles is "very, very magical, which means that a qubit can be divided into two, which has a fundamental change in the whole quantum physics."

Waiting for 80 years for angel particles to appear.

1928, British physicist paul dirac predicted that every elementary particle has its own antiparticle. A few years later, scientists found the antiparticle positron of electrons in cosmic rays, which verified this prediction.

1937, Italian physicist ettore majorana predicted that there may be a special kind of particles in nature, and their antiparticles are themselves. This hermaphrodite particle is called the Mayorana fermion.

Positive and negative, yin and yang, good and evil ... the world seems to be full of opposites.

However, the evidence of the existence of the Mayorana fermion has not been found. Together with neutrinos and Higgs boson, it has become a particle that has been predicted for a long time but cannot be verified for a long time. Now, the research team led by scientists in China has finally found evidence of its existence.

Mysterious amphoteric particles

In the previous quantum anomalous Hall effect experiment, with the adjustment of external magnetic field, an integer quantum platform will appear. This is the usual particle behavior. Mayorana fermion has no antiparticle, which is equivalent to a semi-traditional particle. Therefore, when ordinary superconductors are placed on quantum anomalous Hall effect films, a semi-integer quantum platform will appear outside the usual integer quantum platform.

To this end, the researchers built a hybrid device, placing ordinary superconductor films on quantum anomalous Hall effect films (that is, magnetic topological insulators). After applying a low-intensity external magnetic field, the researchers measured a semi-integer quantum platform, which became the experimental evidence for the existence of chiral Mayorana fermions.

According to Einstein's mass-energy conversion formula, when a particle meets its antiparticle, it will annihilate and release energy. Therefore, the research team called the Mayorana fermion they discovered "angel particles".

In the process of searching for "angel particles", the theoretical team of China scientists predicted what kind of experimental platform can be used to search for Mayorana fermions and what kind of experimental signals can be used as evidence. The experimental team worked closely with the theoretical team and finally discovered the chiral Mayorana fermion, ending the 80-year scientific exploration. Fudan University in China and Shanghai University of Science and Technology also contributed to the experiment.

The quantum computing era it brings is expected.

What is the practical significance of discovering the existence of Mayorana fermion for building a stable quantum computer?

At present, it seems that one of the biggest uses is to help China build a more stable and world-leading quantum computer in the future! Quantum computer is a kind of computer with ultra-high speed parallel computing and simulation ability. Its computing power will increase by tens of thousands of times.

Ordinary computers can only solve problems one by one in chronological order, while quantum computers can solve multiple problems at the same time. This super-fast speed may completely change all industries. For example, weather forecast accurate to the second, predictable traffic conditions, structural exploration of new drug components, exploration of outer space, artificial intelligence and automation, etc., all the undertakings that need computers to explore one by one through exhaustive methods at present may be completed in an instant.

Zhang Shousheng has always mentioned that the value of human civilization is simplicity. He thinks it is really awesome to talk about the main road in simple words so that everyone can understand it.

His favorite story is about Dirac:

What is the root number of 4? Very simple, 2 and -2, Dirac, a British theoretical physicist and one of the founders of quantum mechanics, found this answer very wonderful when he was in junior high school. Why do radical signs always have positive and negative roots?

Dirac suddenly made an amazing prediction from the root sign, and concluded that all the basic particles in the universe have antiparticles, electrons have antiparticles, protons have antiparticles, and neutrons have antiparticles. This is a very, very amazing prediction.

Positron was discovered in the experiment of 1932 C.D. Anderson.

1956 American physicist Chamberlain discovered antiprotons in Lawrence Berkeley National Laboratory. He collided with pairs of high-energy particles accelerated by a particle accelerator in a glass tube, and found that several trajectories suddenly appeared in pairs, and then collided and annihilated each other in a short time. This is the first time that antiparticles have been directly observed.

So far, almost all antiparticles of particles that are relatively stable relative to strong interactions have been found. If antiparticles combine in the same way as ordinary particles, anti-atoms are formed. Matter composed of anti-atoms is antimatter.

In this way, Dirac's genius prediction was confirmed by experiments. So, is there a counterexample? Will there be a particle without antiparticles or a hermaphrodite particle in the universe?

1937, Italian theoretical physicist ettore majorana theoretically proposed the existence of such a particle, which is what we call the Mayorana fermion today, and its antiparticle is itself. Unfortunately, coincidentally, he disappeared mysteriously on a boat trip to Palermo shortly after he proposed the existence of this magical particle, and never heard from him again.

Since then, this magical particle has become the dream lover that physicists have always wanted to pursue, which has plagued the physics community for 80 years.

Zhang Shousheng turned the breakthrough to condensed matter physics. From July 2065438 to July 2007, Zhang Shousheng and his team published a new discovery in the journal Science, and found a marginal current with semi-quantum conductance in the superconducting-quantum anomalous Hall platform, which is very consistent with the theoretical prediction of chiral majorana particles. This is the first majorana measurement result with conclusive evidence in the Hall effect platform system.

Zhang Shousheng named the newly discovered chiral Mayorana Fermion "Angel Particle", which originated from Dan Brown's novel and his movie Angels and Demons. "This work describes the scene of annihilation and explosion of positive and negative particles. We used to think that every particle has its antiparticle, just as every angel has its devil. But today, we found a particle without antiparticles, a perfect world with only angels and no demons, "Zhang Shousheng said.

This also made Zhang Shousheng once again a popular candidate for the 20 17 Nobel Prize in Physics, although he was ultimately defeated again.

Of course, there are some doubts. For example, li miao, dean of the Institute of Astronomy and Space Science of Sun Yat-sen University, commented: "This discovery is not a fundamental particle, but a boundary between a quantum state and a two-dimensional substance caused by extremely low temperature. This state meets the requirements of neutral particles, that is, its inverse state is itself. Because this quantum state requires extreme conditions, it is still far from application. If I explain it in vernacular, it is "condensed matter physics has not captured particle physics."

Simply put, the confirmation of majorana quasiparticles must find more convincing evidence, and majorana's fermions can only continue to be physicists' lovers and dreams.

65438+February 1, Zhang Shousheng, a Chinese American, jumped from a nine-story building in the United States and hastily ended his short life at the age of 55.

Zhang Shousheng is Yang Zhenning's favorite pupil, a foreign academician of China Academy of Sciences, a physicist and the discoverer of angel particles. He has won the European Prize in Physics, the Barclays Prize, the Dirac Prize and the Yuri Prize in Basic Physics. Yang Zhenning thinks he is the winner of the next Nobel Prize.

To Yang Zhenning's surprise, he sent the white-haired man to the black-haired man.

Angel particles and features 1937 was put forward by majorana. It is a fermion, and its antiparticle is completely equivalent to itself. When they meet, they will annihilate each other and release a lot of energy. Nayolana rewrote Dirac equation and got Mayorana equation. But no physicist has found the existence of the Mayorana fermion.

It was not until 80 years later that Zhang Shousheng and his team discovered the chiral Mayorana fermion in the system composed of topological insulators and superconductors, which conformed to the wave equation of majorana Fermi equation and strongly confirmed the existence of Mayorana fermion (angel particle) for the first time. The news was published in the journal Science.

Welcome to pay attention and comment.

I don't specialize in physics, just share some information about "angel particles" I have seen.

First of all, the existence of "angel particles", also known as "chiral Mayorana fermion", was first proposed by ettori majorana. The "antiparticle" mentioned in this passage was put forward by physicist Dirac. He predicted that every elementary particle will have its own antiparticle, which is completely different from the "positive particle"-just like a pair of incompatible brothers. For a simple example, every positive number on the number axis corresponds to a negative number. Although these two numbers are inextricably linked, they are completely two numbers. This predicted angel particle is an exception. He is 0 on the number axis, and the negative number is himself.

Secondly, the term "angel particle" is just an interesting name. This particle has nothing to do with angels, nor with kindness, light and peace. This statement is just Zhang Shousheng's own romantic statement.

So as long as he wants, he can also say that this particle should be called devil particle.

This is a great discovery, but there is still a long way to go to find the real angel particles. What is discovered at present is not the predicted elementary particle, but a "quasi-particle" formed by a beam of electrons. They behave like predicted angel particles.

For example, a big stone blocks the road, and one person predicts that someone must be able to move the stone. After several decades, several people said with great excitement that we had found a way for twenty people to move the stone together. So the predicted Hercules was still not found, but these twenty people achieved the same effect as Hercules, and finally moved the stone away and solved a big problem.

In fact, Zhang Shousheng is not the main leader of this paper, but the planner.

Therefore, the first author of this paper is not Zhang Shousheng. Of course, this is just authors rank's problem, and his contribution to this research is still great.

Moreover, it should be noted that the first authors of this paper are He Qinglin and Pan Lei from UCLA. As can be seen from their names, they are both from China.

In addition, Shanghai University of Science and Technology also participated in the experimental research. Even before He Qinglin/Pan Lei team, Jia Jinfeng team of Shanghai Jiaotong University published a report on the discovery of the fermion of Mayorana, but compared with the former:

The work of Professor Jia's team is a zero-dimensional version of Mayorana fermion, which is mainly tested by scanning microscope. We study the one-dimensional version of Mayorana fermion, which is mainly made into electronic devices for macro electromagnetic testing.

Therefore, even though the teams of Shanghai University of Science and Technology and Shanghai Jiaotong University have not received so much attention, their contribution to the study of "angel particles" cannot be ignored.

Angel particle is not an official name, but it is named by the discoverer. Prior to this, this particle was called Mayorana Fermion. As can be seen from this name, the majorana fermion consists of two parts, one is majorana and the other is Fermion. Italian theoretical physicist majorana died young, was born in 1906, and disappeared in 1938, but he put forward Mayorana equation and rewritten Dirac equation. The latter is fermion, as a large class of quantum particles, fermion is considered to have antiparticles different from itself, while the other is boson, which has its own antiparticles. Therefore, majorana predicted that there is a special fermion in nature with its own antiparticle, which is called Mayorana Fermion.

The Mayorana fermion only predicted its existence, and its position in nature is obviously lower than that of the Higgs boson, because the task of the Higgs boson is to give the fermion mass, and it is itself a boson. It can be seen that the discovery of the Fermion in Mayorana verifies majorana's conjecture. From the perspective of the history of science, it is more accurate to call this particle Mayorana Fermion, because it was predicted by him. This is like someone telling you that this thing exists, but it is limited by the observation technology at that time. If we want to name the Mayorana fermion an angel particle, we actually have to ask majorana if he wants to, because Higgs, the prophet of the Higgs boson, doesn't like the name God particle very much. From this point of view, the prophet has more weight, and he can make predictions through theoretical equations half a century ago, which is admirable.