preface

Part 1: The Mystery of Quantum Theory

Chapter 1: Quantum is with us
Life does not arise from a grain of sand.
A stable structure made by molecules
Precision machines that drive life
From vitalism to quantum theory
Flexible system of nuclei and electrons
Let's start with the simplest case.
Planetary system governed by gravity
The crucial difference between planetary systems and atoms
Regularities exhibited by hydrogen atoms
Atomism? This strange thing
Chapter 2: The Order Created by Waves
Atoms and fields
The Mystery of the Hydrogen Atom
Schrödinger's solution
Trapped waves create shapes
Let's consider the vibration of a string as an example.
The identity of the force that confines the wave
What's happening in a hydrogen atom?
Digging into the essence of quantum effects
From atoms to molecules
Explaining Chemistry with Physics
The idea that 'electrons are waves'
Schrödinger's mistake
Chapter 3: What is 'Quantum Theory Made Easy'?
The target of quantum theory shifts from 'particles' to 'fields'
What is 'quantum field theory'?
The former has no individuality
How do waves become particles?
The contradiction of being both a wave and a particle
What is the uncertainty principle?
A space prepared for waves
Quantum field theory had flaws
Quantum theory made easy to understand and its enemies

Part 2: Two Genealogies of Quantum Theory

Chapter 4 Bohr vs. Einstein
Max Planck discovers energy quanta
Innovations brought about by Einstein
Light resembles gas molecules
The quantum theory of light, which was considered a failed theory
Bohr's atomic model, which he created after much thought
A patchwork of theories
Bohr-Einstein debate
Who wins the debate?
Chapter 5: Heisenberg vs. Schrödinger
Born, who sought new dynamics
Radical Heisenberg
Heisenberg's microscope
Heisenberg, who inherited Bohr's methodology
Schrödinger, who valued images
Criticism of Schrödinger and its consequences
Chapter 6: Dirac vs. Jordan
something vibrating
Electrons and photons are particles
The brilliant techniques of the genius Dirac
The magic of creation and destruction
Dirac's Sea
Limitations of Dirac's method
Electrons and photons are waves
What is uncertainty?
Elementary particles are created in the field
Where do waves come from?
Why was quantum field theory not accepted?
Cursed Physicist Jordan

Part 3: Bringing Quantum Theory Back Within the Scope of Common Sense

Chapter 7: Schrödinger's Cat and Quantum Computers
What is Schrödinger's cat?
There is no cat that is dead while still alive.
If the overlap is maintained
A feasible 'cat state'
Structure of a classical computer
Quantum computers use cat states.
Challenge from a 0.2% accuracy rate
Another quantum computer
Chapter 8: Does History Diverge?
Which way did you pass? Experiment
If you make the slit plate move… …
Did the Boer camp really win?
Are particle and wave nature exclusive?
Is human observation necessary?
Which one did you actually pass through?
The process of interference is a 'history'
If history is not interfered with, will it diverge?
Talking about 'history' through quantum theory
Chapter 9: Far Away, Yet Entangled?
What is quantum entanglement?
Investigating quantum entanglement using light
Do the observation results influence each other?
Things you only know when you count them
Quantum entanglement is not telepathy
Bell's inequality
Problems for which no solution has been found and their meaning
Postscript_True Quantum Theory
annotation

Why do materials maintain complex yet sophisticated forms?
Background of the emergence of quantum theory and the results of quantum effects

What is a "quantum"? The dictionary definition is "the smallest indivisible unit of energy." Quantum theory is a general term for "physical theories developed from the perspective of quanta."
Physical effects that can only be explained through quantum theory, or 'quantum effects', are found in all kinds of physical phenomena related to matter.
The fact that electrons are not attracted to the nucleus but orbit it at regular intervals, that atoms do not decay but are arranged in a regular manner to form a crystal structure, and that this crystal structure forms and shapes macroscopic materials is all thanks to these quantum effects.
Moreover, quantum effects can be used to explain cosmic phenomena such as the structural stability of cell membranes and the maintenance of life, the quick bending of heated metals and the transparency of glass, the continuous flow of time, and the birth of planets in the solar system.

Part 1 of the book, "The Mystery of Quantum Theory," explains the background of the emergence of quantum theory by citing examples of physical phenomena that cannot be explained by classical physics.

According to classical physics based on Newtonian mechanics, two adjacent particles are either attracted to each other or moved away from each other.
Newton's equations of motion do not provide a mechanism to maintain the distance between two particles at a constant level, and therefore, the nucleus and the electrons surrounding it cannot merge and become stable.
Electrons that lose energy through interaction with the electromagnetic field fall toward the nucleus, much like a satellite that loses energy through friction with the atmosphere and falls to Earth after leaving its orbit.
Matter decays when nuclei and electrons stick together to form an electrically neutral mass.
It is impossible to have a form at all.
Quantum theory emerged as a leap of thought to explain phenomena that could not be explained by conventional mechanics: "Could it be that the components of matter, such as electrons, are different from particles?"

In Part 2, 'The Two Lineages of Quantum Theory', unlike the theories of Heisenberg and Bohr, which have been considered mainstream in the field of quantum mechanics, the wave field concepts of Einstein, Schrödinger, and Jordan, which were often considered heretical, are used to explain quantum phenomena, thereby discussing what lies at the root of physical phenomena that we commonly encounter in our daily lives.

The author points out that one of the reasons quantum mechanics has become such a difficult and complex subject to understand is because the complex theories of Bohr and Heisenberg have been accepted as the standard for quantum theory.
Bohr and Heisenberg adopted a methodology of fitting theories to formulas and observations based on the idea that 'the essence of nature is something that humans cannot know anyway', which was 'first treat electrons as particles, and then apply the uncertainty principle'.
On the other hand, Schrödinger and Jordan were not satisfied with obtaining a formula that matched the phenomenon, but tried to examine what was at the root of the phenomenon by using specific images such as vibrations and waves as guiding principles.
The author highlights the achievements of Schrödinger, who solved the stable state of atoms, which is impossible according to Newtonian mechanics, as waves, and Jordan, who assumed that the 'field' that exists widely within electrons creates waves.

Can a cat be dead while still alive?
To understand true quantum theory

Finally, in Part 3, 'Returning Quantum Theory to the Scope of Common Sense,' theories and phenomena that are difficult to understand in a realistic sense, such as a cat being alive and dead at the same time or the observation itself affecting the state, are explained through the movement of waves.

In conclusion, electrons are waves, and they move like particles only when the standing wave is not disturbed by external forces.
Waves trapped in an electron field form a stable resonance state when specifically arranged.
These resonance patterns all have the same energy and behave as if they were a single particle.
This is why electrons sometimes appear like particles.
In other words, the author argues that the core of quantum theory is that wave and particle nature are not exclusive, and that standing waves that form resonant patterns create order and make complex events such as life possible.

The author speaks very firmly.
“It is impossible for the waves of a living cat and a dead cat to actually overlap.”
Beta decay of a neutron, which can kill a cat by breaking a flask containing poison gas, occurs with a 50% chance or not.

In cases where beta decay occurs, the history branches off into different directions every few seconds.
In the case of chemical reactions, the states before and after the reaction do not interfere with each other, so each time a molecule undergoes a chemical reaction somewhere in the world, a separate history is created.
It is hard to believe that all these countless histories exist in parallel universes.
Histories distinguished by transitions to a non-interfering state (deinterference), such as beta decay or chemical reactions, are merely hypothetical, expressed in equations. It is reasonable to assume that one of these is actually realized. (p. 220)

However, the author says that wave overlap does not occur at all, and that it is a very common phenomenon at the atomic level, just as ripples on a surface of water overlap or waves overlap when the strings of a musical instrument are plucked.
We then examine how this quantum theoretical wave superposition, or 'Schrödinger's cat' state, can be utilized in quantum computers.

Quantum theory is by no means an absurd, incomprehensible theory, as represented by the famous double-slit experiment, which is said to be about a 'living dead cat' or 'wave-particle duality'.
The author believes that quantum theory is a theory that “clarifies that the world is changing flexibly through the interference of minute waves that exist at the root of matter.”