My current research field is materials engineering, but there were times when I was interested in other disciplines.

This time, I will introduce "quantum theory", "dimensional theory" and "nothingness" that I found particularly interesting among them!

These disciplines may seem unrelated, but they are all closely related.

## quantum mechanics

I remember being moved to hear the class when I was in my first year of university.

Some students seem frustrated because they sometimes come from the surprising assumption that light is a grain and a wave.

Anime and similar nonscience tend to be taken up, and many people may know the name.

### What is light?

At the end of the 19th century, the Physical Society argued that light was a grain or a wave.

Young's experiment with light diffraction proved the opinion of acting as a "wave" that was the mainstream at the time.

On the other hand, it turned out that Einstein's photoelectric effect made light a wave and could not be explained.

As a result, the surprising conclusion that light acts as both "grain" and "wave" was drawn!

On the other hand, de Broglie, who learned that light, which was thought to be a "wave", has the property of "grain", and gets the idea of reversal.

It is the idea that all materials are "material waves" in the micro world, which are not only "grains" but also "waves".

In the micro world, it is thought that it behaves as a "wave" until observation, and as a "grain" when observed.

### The World of Probability Theory

The idea that the location of the object is not determined until observation is observed, and that the observation result is based on probability theory also causes criticism.

From the perspective of the mechanics that were supposed to be predictable, probability theory does not predict no matter how much information is.

Einstein attributed physics to imperfects and criticized "God doesn't roll the dice."

In addition, this probability theory shrinks the wave as a grain at the moment of observation, and other events contract to one.

This also led to a rebuttal of "Schrödinger's cat" in the sense that things would not be decided until observed.

### Convergence vs Multiworld theory

The question remains about what happens to cats that exist simultaneously in the box at the moment of observation.

In response, the Copenhagen school proposed that multiple probabilities converge by observing.

However, there were many objections such as what factors causes the probability to converge and what the conditions of observation are.

On the other hand, "multi-world theory" is an idea that accepts superposition as it is.

The idea is that the world is more divided, rather than converging in one.

Multi-world theory has also been incorporated into science fiction and has become widely known as a parallel world/parallel world.

## Dimensional theory

Doraemon's 4D pocket is not the so-called "4D space-time" of "space 3D + time 1 dimension".

In addition to the "three-dimensional space" in which we live, dimensional theory is to think that there are further spatial axes.

It is fun to think from a familiar low dimension to an invisible high dimension, and to imagine an unknown super-solid!

### Think from a low-level

The first idea is to increase the dimension by shifting the shape.

If you shift the "point" that is a 0-dimensional figure along the first axis, it becomes a "line" that is a one-dimensional figure.

If you shift the "line" that is a one-dimensional figure along the second axis, it becomes a "plane" which is a two-dimensional figure.

If you shift the "plane" that is a two-dimensional figure along the third axis, it becomes a "three-dimensional" shape.

With this idea, you can shift a 3D shape along the 4th axis to obtain a 4D shape.

In practice, there is no fourth axis, but we can think of four dimensions from this idea.

The two ideas are to reduce the dimension by breaking down the shape by one.

The cube, which is a three-dimensional figure, consists of "square", which is six two-dimensional figures.

A two-dimensional figure, a square, consists of four one-dimensional shapes, lines.

The "line", which is a one-dimensional figure, is made of two 0-dimensional figures, "dots".

According to expectations, the "super cube", which is a four-dimensional figure, should be made from the "cube", which is eight three-dimensional figures.

### Half-hearted dimension

Also 1,2,3… and integers are often seen, but in fact there are halfway dimensions.

In order to do so, it is necessary to define the following "Hausdorf dimension".

"When the amount becomes N^D times when the side of the shape is l times, the amount is determined as n-dimensional"

For example, if the sides are doubled, the line will be 2=2^1 times, the square will be 4=2^2 times, and the cube will be 8=2^3 times.

The fractal figure famous for Romanesco has a halfway dimension in the Hausdorf dimension.

Other known products include Koch Curves, Sherpinski Gaskets, and Menger Sponges.

These shapes are hypothetical shapes and solids that do not exist in reality, but they have interesting properties.

### High-dimensional and string theory

Currently, the existence of high-dimensional space is directed by many people, and there is a theory that there is an 11-dimensional presence in some cases.

The presence of gravity is the reason why the presence of a higher dimension that has not actually been observed is believed.

It is said that the power of this world is derived from "electromagnetic force", "strong force", "weak force" and "gravity" from one force.

However, it bothers researchers that only gravity is very weak compared to the other three forces.

There is also an unsubstry theory that a part of gravity may be leaked to multiple dimensions as a reason.

Another theory is that the smallest unit of dimension is not a point but a "string", and the high-dimensional space is small and folded.

This is called super string theory, and it is expected that contradictions such as quantum mechanics may be solved.

## No

I've always wondered "no sound", "no taste", "no color" … It's not without it.

I've always thought about what's in vacuum, but I couldn't get an answer.

Considering what is in an empty space, the tondemo theory that the universe was created from nothing can be convinced.

### No step-by-step

"Vacuum" is what we think of when we hear nothing, but this is a space filled with gases with pressure lower than atmospheric pressure.

It is said that the first time to create a vacuum was Tricheri, which measured atmospheric pressure using mercury.

He used the high density of mercury to create space from cylinders without air.

However, this vacuum contains mercury particles that have become a gaseous, and is not without it.

It seems that it is thought that there is nothing to remove particles further from here, but there is also an easier way.

It is the space between the nucleus and the electron in the hydrogen atom which thinks next.

The protons and electrons that make up the atoms should be the smallest particles, so there should be nothing in between.

In practice, however, even in this space, there is a Higgs field.

This limits the speed of non-light materials and has been confirmed to exist as a Higgs boson.

### "Nothing" does not exist.

Even if all particles are removed by all means, there is no complete "nothingness".

Heisenberg's uncertainty principle in quantum theory prevents energy from being completely 0.

The presence of energy in empty spaces is evidenced by the "Kashmir effect".

The energy state is always in a state of "fluctuation", and in empty spaces, the pair generation and extinction of particles occur.

When energy is thought of as a wave, it is like a mountain and a valley being born and disappearing with constant shaking.

Since the wave of energy is considered as an elementary particle by the idea of quantum theory of the field, nothing can exist.

In conclusion, it is impossible to make "nothing" in our world that is truly nothing.

Since there is no "nothing" in the true sense, the Big Bang theory that created the universe from nothing is derived.

Today, it is thought that the universe was born due to the rapid expansion of this fluctuation of energy.

### What is in nothing?

There are several types of elementary particles that build a "place" that conveys power in a place where there should be nothing.

The quarks and leptons that make up the material, and the gauge and Higgs particles that transmit force from it.

Electromagnetic force: photon, strong force: gluon, weak force: week boson, gravity: graviton corresponding to each.

In addition, there are other materials in the space that is thought to be nothing more.

Dark matter is an undiscovered substance that does not match calculations when calculating the total weight of the universe.

In addition, the total energy of the universe is not calculated, and the existence of dark energy is expected, but it has not been discovered.

In this way, there are facts that we are not even aware of before we think about nothingness.

## Overall I like fluffy learning.

These disciplines are more of a mysterious phenomenon than science, and can be enjoyed in the humanities.

On the other hand, because it is difficult to explain in mathematical formulas, it is often abused by tondemo theory, similar nonscience, and religion.

It is recommended that you study and deepen your understanding as you do not understand, and try to defend yourself.

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