In the history of human science, many experiments have been done, and experiments are also an important force in promoting the continuous development of human science. But there are some experiments, and the results are horrifying to scientists.
For example, the famous electron double-slit interference experiment.
This experiment is a collision between classical physics and quantum physics . The collision process produced "fierce sparks" and also promoted the development of quantum mechanics .
First, let’s take a brief look at classical physics, which we are very familiar with. More than 300 years ago, Newton was born, proposing the law of universal gravitation and the three laws of mechanics that have ruled the world of physics for hundreds of years, laying the foundation for classical physics.
Newton's classical physics describes the movement laws of macroscopic objects in the low-speed world. Everything in the universe is deterministic, describable, and has a causal relationship.
In this world view, there are objective natural laws in nature. We only need to find them to describe everything in the universe. This is also the so-called " determinism ": everything can be described and there are laws. Circular.
And our daily life experience has indeed told us this, which is very consistent with our perception, so everyone has no doubt about Newton's classical physics.
So much so that when quantum mechanics came out, Einstein Schrödinger and other physics giants could not believe the strange phenomena in quantum mechanics, let alone ordinary people. It can be seen that classical physics has long been ingrained in people's minds.
Let’s talk about why the electronic double-slit interference experiment is scary.
Long story short. An electron transmitter gun with a baffle with two slits and a receiving screen behind the baffle.
In people's inherent concepts, electrons are real particles. So when electrons are fired into two slits, two stripes should appear on the screen.
But in fact this is not the case. What appears on the screen are interference fringes of alternating light and dark. This shows that electrons are not particles, but also a wave, with wave characteristics. After the electrons pass through the two slits, interference occurs and interference fringes are produced.
Then the scientists emitted single electrons one by one, but the interference fringes still appeared, which was incredible. How can a single electron interfere? Could it be that the electrons passing through two slits at the same time interfered with themselves?
Scientists are very smart. They thought of installing detectors next to the slits to see how the electrons pass through the two slits.
At this time, something incredible happened: when scientists tried to observe, the interference fringes disappeared, and only two fringes appeared. And when the detector was turned on again, the interference fringes appeared again! It looks as if the electrons know that scientists are observing!
This has scientists puzzled!
The Copenhagen School headed by Bohr proposed the "principle of complementarity", believing that not only photons, but also electrons have wave-particle duality, being both particles and waves. We cannot determine the position of the electron, we can only use probability to describe it, and we can only calculate the probability of the electron appearing at a certain position. The only way to determine the probability of an electron is through observation.
Einstein, Schrödinger and others cannot accept this "uncertainty" interpretation, because it would mean that the world is also uncertain and indescribable, which runs counter to the "determinism" in classical physics.
This also led to the idea that "God does not play dice" put forward by Einstein in the debate with Bohr.
The debate between Einstein and Bohr lasted for decades. At present, the " uncertainty principle " has the upper hand and has become a theory recognized by the mainstream scientific community.
However, the exploration of quantum mechanics is far from over, because as the physicist Feynman said: No one really understands quantum mechanics. There is still a long way to go to explore quantum mechanics!
