In this paper, the author participated in the series of soliciting articles of “hundred science” and “great basic science”
Human beings have entered the era of civilization since they had written 5000 years ago. At the same time, it also began to explore the world continuously. The period that really made human civilization develop by leaps and bounds was the beginning of the industrial revolution hundreds of years ago, and mankind entered the era of scientific and technological development.
The rapid development of science and technology is inseparable from the great knowledge of science. Science consists of many disciplines. Physics is the main discipline to reveal and recognize the world. It is the rapid development of physics that enables human beings to have more understanding of the nature of all things in the world after entering the era of Science and technology. At the same time, the rapid development of physics also enables human beings to realize the dream of flying to the sky and go out to explore the earth The universe.
This is also an important reason why many people like physics, because it can help people understand the world more, and even help people explore the ultimate mystery of the universe in the future. In physics, however, there is always more unknown than known. Although human beings have made great progress in physics, there are still many phenomena that we can’t explain. Today we are going to talk about a very simple physics experiment in high school.
Although it is a simple physical experiment, it shows us a mysterious phenomenon that science cannot explain. I believe many friends know the double slit interference experiment, which is an entry-level knowledge in high school physics class. I believe every science student should have done this experiment.
This experiment is very simple. We prepare a candle and place a baffle with only a long gap behind the candle. The function of the baffle is to make the light emitted by the candle diffract first and become a stable coherent light source. In this way, interference can be eliminated and the test results can be observed more clearly. Then, a baffle with two long slits is placed at the back. The second baffle is used to make the coherent light become the same two columns of light sources. When the two columns of light sources interfere, the same phase effect will be enhanced, and the difference in phase will be offset. Finally, a black screen will be placed to undertake the light and dark fringes generated by the interference.
Through this experiment, the teacher told us that light has wave particle duality, that is to say, light is both a wave and a particle. We are familiar with light. We are dealing with it every day. Its speed is constant, the fastest speed seen by human beings. Other substances can only approach the speed of light infinitely.
In the eyes of many people, the double slit interference experiment is a very simple experiment, which proves the wave particle duality of light. But no one would have thought that this seemingly simple experiment has finally become a big problem in the scientific community, and it has not been able to solve it so far. What’s the matter?
Wave particle duality exists not only in photons, but also in protons, electrons and other elementary particles. They are not only particles but also waves. Therefore, in the double slit interference experiment with electrons, there will be bright and dark lines, and the electrons are easier to observe.
Therefore, when scientists do double slit interference experiments, they use electrons, and single electrons, because it is easier to observe the characteristics of light. Physicist Klaus used an electron emitter to emit a single electron into one of the slits of the double slit baffle. After one electron is sent out, a second electron is sent out at a tiny interval of time. Unexpectedly, light and dark stripes can also appear. You know, before using a candle as a light source, a lot of particles passed through the double slit at the same time, while a single electron could also produce light and dark stripes through the double slit, which means that an electron passed through the two slit at the same time and interfered with itself.
It is not difficult to understand that the electron emission becomes a wave through the double slit, which proves that the electron also has wave particle duality. But the next experiment really made the scientists lose their composure. In order to better record and observe the process of electrons passing through the double slit, the scientists installed a particle camera in front of the double slit. But a strange scene happened. At this time, the electrons from the electronic transmitter arrived at only one point on the screen, and the ripple disappeared.
This shows that the electron does not pass through the double slit at the same time. The electron only shows one side of the particle, but not the wave side. What’s going on? When the scientists removed the particle camera, the shading patterns on the screen appeared again. When they installed it again, the patterns disappeared. This shows that the observation of the electron will affect the state of the electron. Whether the electron is a particle or a wave depends on the observation of the outside world.
This is the first time that scientists have met in their exploration and research career. In previous research and exploration, even if they study the micro world, they can record and track the observation through the particle detector, so that the observation process can be better studied since it is saved. However, the wave particle image of the electron can not be tracked and stored by the detector. We can only observe it with the naked eye. Once the detector is involved, the wave side of the electron disappears immediately.
This strange phenomenon seems that electrons are living. When they are discovered, they become particle states. When they are not discovered, they secretly become wave states, completely subverting cognition. In order to further explain this phenomenon, scientists designed a delay experiment, but the result is even worse.
The previous observation happened before the electrons passed through the baffle. This time, the scientists are going to put the particle camera behind the baffle. If the electron changes because the detector is found before passing through the baffle, can the particle be observed by the particle detector after passing through the baffle and completing the fact of wave particle duality?
The principle of delay experiment is to move the detector between the baffle and the screen, let the particles make a choice first, and then observe. When a single electron passes through the baffle, it turns on the detector instantaneously. At this time, the electron has already passed through the double slit. According to the principle, it should show wave particle duality on the screen. However, the result shocked people again. At this time, the interference fringes on the screen were digested and there was only one bright spot left. The characteristics of the wave disappear again, which is equivalent to the reversal of causality.
This mysterious phenomenon of double slit interference experiment has caused a great sensation in the scientific community. Many scientists have also carried out a lot of experiments. No matter how to operate, as long as the particle detector is added in, the ripples of photons and electrons are all digested, and finally only the characteristics of particles are left. But when the particle detector turns off, the interference ripple reappears.
This is completely contrary to the laws of the macro world. At present, scientists have not been able to give a reasonable and correct explanation for this strange phenomenon. Although many scientists speculate that some substance in the particle detector may interfere with the transmission of photons? But for other types of cameras and detectors, the test results are still the same.
It is possible that photons, electrons and other particles are far more complex than we think. Take photons as an example. Although the current scientific view is wave particle duality, scientists are not sure whether this conclusion is completely correct. Perhaps before the strange phenomenon of this experiment appeared, the position of wave particle duality of photons was unshakable. However, after the appearance of strange experimental phenomena, scientists are not entirely sure. It is possible that photons have a third feature, which is the mysterious phenomenon that the strange wave disappears and reappears.
However, science is constantly moving forward. I believe that with the rapid development of human science and technology, the reason for this strange phenomenon will be solved in the future. At that time, human beings may have a new understanding of the characteristics of photons and electrons.
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