In 1927, the basic form of quantum mechanics had been established. The two mechanical systems, matrix mechanics and wave mechanics, provided fundamental theoretical support for the quantum world.

The importance of these two mechanics is the same as the status of Newtonian mechanics in classical physics. And people also discovered that Newtonian mechanics is just a special form of matrix mechanics, and matrix mechanics includes Newtonian mechanics.

At the same time, new mechanics also made new explanations of physical reality. In summary, there are three main points: Born's probabilistic explanation of the wave function, Heisenberg's uncertainty principle, and Bohr's complementarity. principle.

These three points are that what we often call the Copenhagen Interpretation is the currently recognized orthodox explanation of the nature of the world by quantum mechanics. The Copenhagen Interpretation has now become a synonym for quantum mechanics. The Copenhagen Interpretation is Equivalent to quantum mechanics.

So where does the term Copenhagen Interpretation come from?

In fact, before Heisenberg used this term for the first time in 1955, there was no such term. After that, the word spread rapidly and slowly became synonymous with quantum mechanics.

Then why is it called the Copenhagen Interpretation? Instead of calling it the G?ttingen interpretation? Munich Interpretation?

The reason is Bohr and the research institute he established in Copenhagen, which attracted a large number of young talents who contributed to quantum mechanics and trained many young scientists.

Of course, there are Heisenberg and Pauli. They eventually became the heads of the physics departments of the University of Leipzig and the Institute of Technology in Zurich, including Bonn of the University of G?ttingen. They all had the same interpretation of quantum mechanics. .

Bohr has always played the role of the godfather in the development of quantum mechanics. At that time, there was a saying among all the young graduate students that all roads lead to "No. 17 Piao Putang Road". This is the address of the Bohr Institute.

Hence the Copenhagen Interpretation. Of course, we will also refer to those who hold the Copenhagen Interpretation as the Copenhagen School.

Let’s talk about what is the Copenhagen Interpretation? The following content is very important. This is a very important lesson for you to understand quantum mechanics.

Probabilistic explanation and uncertainty principle directly shatter the determinism and causality of classical physics. The uncertainty principle and complementarity principle shatter the objective reality of the classical world.

Probability explains that we can only statistically describe the mechanical quantities of quantum objects. For example, we cannot say exactly where electrons can be found. We can only say, What is the probability that an electron is present somewhere.

Moreover, electrons appear somewhere without any causal relationship. Everything is random. This not only denies the decisiveness of reality, but also denies causality.

For another example, the time it takes for a single radioactive atom to decay is uncertain. We cannot accurately tell the time it takes for a single atom to decay. We can only give it statistically, it takes half of the time it takes for a large number of atoms to decay. time.

And there is no reason why a single atom decays at a certain moment. This in turn denies determinacy and causation.

For another example, there is no certainty about the time when an excited state electron transitions back. You cannot tell at which moment this electron will transition back. You can only give a probability, and the electron will transition back at a certain time. There is no reason for this momentary jump.

Wait, there are many examples like this in the microscopic world, but none of them satisfy the determinism and causality of the macroscopic world.

The uncertainty principle says that not only the mechanical quantities of quantum objects must be described by probabilities, but also we cannot accurately measure the position and momentum information of quantum objects at the same time from the beginning.

Doesn’t your determinism mean that as long as we can measure the motion state of every particle in the universe at this moment, based on the interactions they experience, as long as the computing power is powerful enough, we can calculate the past, present and future. .

Now you can’t even measure the initial state of particles accurately, so it’s not conclusive.

Therefore, the uncertainty principle fundamentally denies determinism.

The uncertainty principle also says that since we cannot accurately measure the momentum and position information of a quantum object at the same time, then we think that if it cannot be measured, it means there is none. For example, we cannot accurately measure the quantum object at the same time. The position and momentum of the electron means that the electron does not have simultaneously determined momentum and position information at any moment.

This statement directly denies the objective reality that is independent of the observer, and links the objective reality with the observer. Only the quantities that we can measure will be considered to be real. .

Bohr’s principle of complementarity is even more absolute. He said that objective reality cannot be independent of the observer, that is, there is no objective reality before there is observation.

For example, when an electron is not observed, it is nothing. We cannot tell what it is now? To describe this problem, you can even think that electrons do not exist. Only after we observe electrons experimentally can we say that they are particles or waves.

Because before there is no observation, microscopic particles will exist in a superposition state and have no definite eigenvalues, so we can even think that before there is no observation of electrons, it has no position information, no velocity information, only After observing it, we can say that the electron exists, whether it is a wave or a particle, and we can think that other mechanical quantities of the electron exist objectively.

This statement is simply unbelievable. In fact, what Einstein couldn't accept the most was Copenhagen's denial of the existence of objective reality. Although Einstein could not accept the denial of determinism and causality. He also said "God does not play dice", but it did not make Einstein's blood pressure soar. After all, as early as 1916, Einstein had discovered violations of causality and determinism in quantum theory.

But denying objective reality, Einstein really never expected it, so Einstein said angrily, does the moon not exist if I didn't look at it? Einstein believed that objective reality is independent of the observer. Wouldn't the earth exist without humans?

Wouldn’t the universe exist without humans? I believe you have heard that the Copenhagen interpretation of the nature of the world is difficult to accept. But the Copenhagen interpretation is like this. It is still the mainstream interpretation of the world by quantum mechanics. So far, no violation of experiments has been found.

Therefore, we now have two ways to go, one is to accept the Copenhagen Interpretation unconditionally, and the other is to stand up and fight back against the Copenhagen Interpretation like Einstein.

Then I will have completed the task of popularizing quantum mechanics. In fact, you don’t need to continue reading the rest of the content.

However, we believe that the vast majority of people, like Einstein, cannot accept the Copenhagen interpretation, and are even less willing to abandon objective reality. Then we will continue to seek other explanations of the nature of reality and follow Einstein’s Stan's footsteps lead a decisive battle at the Quantum Summit.

No need to read further.

However, we believe that the vast majority of people, like Einstein, cannot accept the Copenhagen interpretation, and are even less willing to abandon objective reality. Then we will continue to seek other explanations of the nature of reality and follow Einstein’s Stan's footsteps lead a decisive battle at the Quantum Summit.