Push the door of the parallel world

I am not actually this, nor is it in this world. And in the parallel world, I am all these, and even more.

I am not crazy, nor is it telling a science fiction story. According to the multi-world interpretation, these are the facts.

Multi-world interpretation is an interpretation of quantum mechanics, and there are many parallel worlds in the same time and space as our world. The multi-world interpretation also believes that every choice I make in this world will produce multiple parallel worlds: each world corresponds to one of the choices I made. It can be said that in fact all the things that may happen have actually happened or will happen, but they are in different parallel worlds.

What is the impact of the existence of a parallel world on our lives? Should we worry about this? One strategy is that we can completely ignore other worlds. After all, multi-world interpretation has told us that you can’t communicate with another world, let alone meet you in another world. However, if the multi-world interpretation is correct, then there are indeed many novel inferences that can be said to change our worldview.

Subvert your world view

You have multiple identities

There are countless possibilities for everything in the universe, which means that there are countless parallel worlds in the universe, each of which tells a story about the universe. Based on this, we can re-examine the nature of human beings. For example, in a certain world, you may never have killed someone, but you may have had this idea; in another world, you did it; and if you change another world, you will be the most horrible there. The murderer; on the contrary, in another world, you are doing your best to bring peace there.

You are no different from others

Although you are a terrorist murderer in a certain world, don’t worry, in fact anyone will be in a certain world. Although everyone in this world is different, it is clear that everyone will be very similar if other worlds are taken into account.

You can live forever

First, let’s talk about a thought experiment called “quantum suicide.” This experiment only needs to replace the cat in Schrödinger’s cat experiment with an experimenter. According to the classical quantum interpretation, every experiment, the experimenter has half the probability to survive, so after any experiment, the probability of the experimenter surviving will be lower and lower. However, according to the interpretation of many worlds, no matter how many experiments, there will always be a world in which the experimenter will never die, and the probability of survival is always 100%. This situation is called “quantum eternal life.”

Technically, everyone can live forever in a certain world. Although the traditional view is that we live in the world for a while, then rot in the ground and return to various molecules. But the parallel world opens a door for life: even if you die in this world, you still live well in another world, and there are infinite worlds in the universe, so say You can always exist in this universe unless the entire universe is destroyed.

We are just a projection

The British American physicist David Bohm once proposed the holographic cosmology that the independent individuals of the three-dimensional material world directly visible to the naked eye are actually a projection of the higher dimensional whole. We cannot understand the higher dimensions. Integrity, and mistakenly believe that what we see is an individual. This view is actually similar to the interpretation of many worlds. The multi-world interpretation holds that the whole universe is a whole composed of infinite worlds, and the world we observe is only a small part of the reality in this universe, and the others are hidden from view. So, we are just a shadow cast by the entire universe.

Reality is created by us

Although we can only live in one of these worlds, we are involved in the creative process of the world. Every quantum experiment, every choice, will determine the direction of our world. The world we live in has a unique past, we may not be able to change, but in the future it will evolve into multiple worlds, some of which are in our hands. Want to live in a beautiful world? Then do your own big choice.

Maybe nothing is real

There are countless worlds in the universe, and each one may be true. However, since everything is real, it can be said that nothing is true. Our world is just one of countless dreams. Although it seems that this view has a negative component, this may be the case.

All of these are our inferences about the parallel world, but you have to understand that in the future there will be hundreds of millions of you considering these inferences from different angles, which will give you hundreds of millions of feelings, and one of them will eventually become You in this world.

Why do you have a parallel world?

Intractable Schrödinger’s cat

The parallel world is so mysterious, how many scientific bases are there? Or is it just a scientist’s cranky thoughts? Quantum theory gives a clear answer: the parallel world is based on science, although we can’t confirm it by observation.

In the quantum world, microscopic particles can be in multiple states at the same time. This state is called a superposition state, and physicists can describe it with a mathematical tool called a wave function. But in reality, when we detect microscopic particles, the superposition of the particles disappears automatically, and finally only one result is obtained. Why? The traditional quantum theory holds that once an observer observes a particle, the wave function will “collapse” and become a state in which it randomly becomes. This traditional view is the interpretation of Copenhagen, mainly by the Danish physicist Niels Bohr and the German physicist Werner Heisenberg in a joint study in Copenhagen in 1927.

The Austrian physicist Erwin Schrödinger did not agree with the interpretation of Copenhagen, so he gave a very famous thought experiment – Schrödinger’s cat. If a cat, a radioactive nucleus, and a glass bottle containing a highly toxic gas are placed in a closed box, when the detector inside the box detects a decaying particle, it breaks a glass bottle with a highly toxic gas. Will kill this cat. The radioactive nucleus has a half probability of decay, but if not observed, the decaying particles are simultaneously in the superposition of existence and non-existence. After the experiment is carried out for a period of time, the cat will be in a superimposed state of life and death, unless you open the box to observe the internal situation, so measuring the state of the cat will cause the cat to live and die superimposed to a unique state. That is, the wave function collapses.

The biggest question in Copenhagen’s interpretation: Why does the measurement cause the wave function to collapse? How is the wave function collapsed? These questions have always been difficult to answer and have become the biggest weakness of Copenhagen’s interpretation.

So many world interpretations come. It was first proposed by American physicist Hugh Everett in 1957. The multi-world interpretation believes that every measurement has already “occurred”, but is in a different “world” or “universe”. Thus, the wave function does not collapse at all, and the state of the particle is still superimposed. For example, for Schrödinger’s cat, Everett believes that after opening the box, the universe splits into two worlds: one of the world cats is alive, and the other world cat is dead. Once they split up, these worlds will go their own way and there will be no intersection between them.

Knock the door of the parallel world

A quantum measurement can produce two worlds. If we often do quantum measurements, wouldn’t we have to create an infinite number of different worlds? In order to explain the quantum measurement problem, is this the case? This problem seems confusing, but it is not so inconsistent.

In order to understand why multi-world interpretation is like this, let’s compare classical physics with quantum physics. In classical mechanics, objects can have certain states, and they can all be observed directly, but not in the quantum world. For example, a microscopic particle in which there are two directions of spin: up and down. If it is classical mechanics, then the possible states of the particles are:

“Spin up” or “spin down”

For quantum mechanics, the particles are in the superposition state of all states at the same time. We can express this superposition state in the following form:

“Spin up” + “spin down”.

Among them, the above “+” means to superimpose the two states together.

In order to describe the measurement process of this superposition state, we have to add an observer. But this does not mean that you need an observer with “consciousness”. We can just have an instrument that can detect the microcosm. The observer can be a living person or just a video recorder. To avoid confusion, we only call it an “instrument.”

In most cases, the state of the instrument and the particles are independent of each other. If you take the instrument into consideration, there are two situations. According to the traditional view, when the instrument observes particles, the quantum state collapses into one of two possible states: spin up or spin down, which is the case:

(“Spin up”; the instrument says “up”) or (“spin down”; the instrument says “down”).

So why not change “or” to “+”? Thus, when the instrument observes particles, the final situation is this:

(“Spin up”; the instrument says “upward”) + (“spin down”; the instrument says “down”).

This situation means that the instrument also enters the superposition state with the particles, and the original wave function of the particles will not collapse. The instrument enters the superposition state, indicating that it is in multiple states, but we only get one of the observations in reality, and never found that the instrument can display multiple observations at the same time. Why is this?

Because in reality, in addition to this particle and instrument, there are other things: here is the other things on the earth, and the outer space of the earth is vast and innocent. These things – they are called “environment” in combination – are also quantum states. The photons and air molecules in the environment will constantly collide with the instrument, so that we can’t isolate the instrument from the environment, but we should take the environment into consideration. Thus, the superposition state of the system can be written in the following form:

(“Spin up”; the instrument says “upward”; environment 1) + (“spin down”; instrument says “down”; environment 2).

It can be seen that the environment has split into two separate environments. This means that when we do quantum measurements, the wave function never shrinks, but the universe will have two worlds that have nothing to do with each other.

In the above discussion, we only used the basic laws of quantum mechanics, so quantum mechanics itself contains the ideas of parallel worlds, whether you like it or not.

Interactive parallel world

a large and limited parallel world

As I said before, Everett’s multi-world interpretation is to make the wave function an important part of the theory, and the predicted results are in perfect agreement with the experimental results. But what exactly is the wave function? Is it realistic or is it just a computational tool that we invented? What is the reality?

To solve this confusion, physicist Howard Wiseman and his colleagues from Griffith University in Australia recently found a way. In simple terms, their approach is to remove the concept of wave functions and replace them with a large but limited parallel world. They claim that our world shares the same space as many other worlds, and each world follows Newton’s classical laws of physics. The particles of our world can produce a subtle force with particles in all other worlds. And what we think of the weird phenomenon of the quantum world is the result of the collision of these worlds. If the interaction between these worlds does not exist, or if there is only one world, then all quantum phenomena will disappear and Newtonian physics will rule everything.

This theory is called the parallel world theory of interaction. In addition to the concept of no wave function, this theory differs from the multi-world interpretation in that the number of parallel worlds is finite; even parallel worlds exist until quantum measurements; parallel worlds can interact with each other through corresponding particles. effect.

To prove that their theory is indeed feasible, Wiseman and his colleagues used their interactive parallel world theory to explain some quantum phenomena. They chose a typical experiment, the double-slit interference experiment. In this experiment, photons are emitted one by one from the emitter, passing through two parallel slits, to the back of the master. If the photon is just a particle, then you will see two spots on the plate that correspond to the slit. But this is not the case. What appears on the photographic plate is the interference fringes between light and dark. How did interference fringes appear? It is generally believed that a photon is also a wave that can pass through two slits at the same time, and the two waves formed after passing through will interfere with each other. This experiment shows that photons have wave-particle duality.

According to the interactive parallel world theory, each photon interacts with “ghost” photons in other worlds, causing specific changes in the path of photons in our world. Wiseman and his colleagues found that only 41 worlds were needed to produce the same interference fringes as the experiment.

Maybe you can really talk to another world.

They said that the interaction between multiple worlds may explain many unsolved mysteries such as gravity. For a long time, among the four basic forces of gravity, electromagnetic force, strength and weak force, gravity and other three forces cannot be unified. This is one of the biggest problems in modern theoretical physics. If gravity comes from the influence of other worlds on our world, then it is normal to be incompatible with the other three forces.

In addition, the prediction of quantum phenomena by the Schrödinger equation is equivalent to an infinite number of multiple worlds. If the number of the world is limited, then the Schrödinger equation is only an approximation. Through careful observation and analysis of the experiment, we may also determine how many worlds exist.

However, this theory is still in its infancy and requires a lot of theoretical support. Whether it can completely replace the wave function, physicists are still not sure. But if this theory is correct, then there is an exciting possibility: we can experiment to find evidence of the existence of other worlds, and even indirectly communicate with other worlds. Maybe one day, you will really talk to you in another world.