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Under quantum mechanics
Electrons and photons have the properties of particles and waves at the same time, and their physical properties are contradictory. Using the standard interpretation of quantum theory to explain this seemingly contradictory thing is Bohr and others' "Copenhagen Interpretation".

Although the discussion in this paper is based on electricity, in principle, it is also applicable to microscopic particles other than electricity: photons, atoms, molecules, nuclei, protons, neutrons and other basic particles.

What does the so-called "wave-particle duality" of electrons mean? That is to say, before electrons are observed, waves are scattered in space. However, when the wave of electrons is irradiated by light, that is, when the position of electrons is measured, the wave of electrons instantly collapses and concentrates at one point, forming a "peak", which no longer has the ductility (continuity) of the usual "wave".

That is to say, when electrons are not measured and observed, they show the nature of waves, and when they are observed, they show the shape of particles.

Before observation, the observer will observe electrons somewhere within the extension range of the wave, but he can't know exactly where the electrons will be found. What he can know is the probability of electrons appearing in this place, such as 30%, 3%, and so on.

The mathematical expression of electron wave is "wave function". In different environments, such as the inside of atoms, the equation for solving the electron wave function is the Schrodinger equation, and the electron orbits inside atoms and molecules can be solved through mathematical operations.

Bohr and others believe that there will be no contradiction in explaining the "wave-particle duality" of electrons in this way. An electron wave is a wave that represents the probability that an electron is found. More precisely, the square of the electron wave function (the mathematical representation of the electron wave) mode is directly proportional to the probability that the electron is found.

According to the standard interpretation, microscopic particles such as electrons exist in space without being observed, that is to say, the positions of microscopic particles such as electrons are uncertain before observation. The probability of observing microscopic particles such as electrons is usually described by ~ "position fluctuation".

Before observation, not only the position of microscopic particles such as electrons, but also the state of motion (momentum) is in a state of fluctuation, and the fluctuation of position has a certain relationship with momentum. The smaller the fluctuation of electron position, the greater the fluctuation of its motion state.

The relationship between the position of the electron and the fluctuation (uncertainty) of the motion state can be expressed by inequality, which is called ~ "uncertainty principle" or "uncertainty relationship". According to the uncertainty principle, it is impossible to determine the position and motion at the same time (the uncertainty is zero), and the microscopic world of the universe is dominated by fluctuations.

The difference between different elements is related to how electrons are arranged. The different arrangement of electrons determines the different properties of chemical reactions of various elements ~ which ions are easy to form, which elements are easy to react, and so on.

In other words, the basic principle of chemistry is dominated by quantum theory, which satisfactorily explains why different elements have different properties, and this question has an accurate answer.

Studying the development of electron orbits based on quantum theory has become "quantum chemistry". The properties of various atoms and molecules, as well as the chemical reaction modes that could not be understood before the emergence of quantum chemistry, are now based on quantum chemistry and are gradually mastered by human beings through computer simulation rather than experiments.

According to quantum mechanics, macroscopic objects ~ substances on the scale visible to the naked eye are regarded as a group composed of a large number of atoms, and the physics to study their properties is ~ "condensed matter physics".

One of the achievements of condensed matter physics research is the application of semiconductors. Through condensed matter physics, the physical properties of different types of semiconductors are determined, and various electronic components are obtained by mixing and combining different types of semiconductors.

Such as diodes, diodes, etc. Are composed of different semiconductors, and many of these things are highly integrated, which is the core part of the computer ~ "integrated circuit (IC)".

Integrated circuits are now widely used in personal computers, mobile phones and household commercial appliances. We can say that our modern life has long been inseparable from quantum mechanics.

Quantum mechanics is the basic theory of almost all physical theories, with the only exception of "gravity". The theory of gravity in modern physics is Einstein's "general relativity".

According to the general theory of relativity, a mass object will bend the surrounding space-time (space-time), resulting in the phenomenon of gravity.

Physics based on non-quantum theory is called "classical physics". In this sense, general relativity also belongs to classical physics (general relativity was born more than ten years later than quantum mechanics).

Modern physicists are trying to unify quantum mechanics and gravity. This unfinished theory is called "quantum gravity theory". There are many theoretical candidates for quantum gravity theory, and the most competitive one is superstring theory.

About: superstring theory, multidimensional universe, dark matter and dark energy will be introduced respectively in the following popular science physics.

Let's follow the development of science and explore the ultimate secret of our universe together.