Characteristics of microscopic particle motion

5.
1.
1 Wave-particle duality

At the beginning of the 20th century, the nature of light as both volatility and particle was universally recognized
.

The relationship between the energy E of the photon and the frequency v is

E=hv

In the formula, h is Planck's constant
.

According to Einstein's law of mass-energy connection, the relationship between the energy E of a photon and the mass m and velocity c is

E=mc ²

Combine the two formulas expressing the energy of photons, and use P to denote the momentum mc of the photon, we get

or

In the formula, λ is the wavelength of the light wave
.

According to the wave-particle duality of light, French physicist de Broglie predicted in 1924 that microscopic particles also have wave-particle duality, and the wavelength of motion of microscopic particles is

In the formula, v is the speed of microscopic particle movement
.

The electron diffraction experiment in 1927 confirmed De Broglie’s prediction that microscopic particles have wave-particle duality
.

This property of microscopic particles determines that classical Newtonian mechanics cannot be used to describe their motion state, but quantum mechanics must be used

5.

1.
2 Uncertainty Principle

In 1927, Heisenberg proposed that because microscopic particles have wave-particle duality, it is impossible to measure their spatial position and momentum at the same time
.

The measurement deviation (uncertainty amount) of microscopic particle position is △x, and the measurement deviation of momentum is △P, then the uncertainty relationship can be expressed as

or

The uncertainty relationship shows that if one of the position and momentum of the microscopic particles has a small measurement deviation, the measurement deviation of the other is bound to be large
.

5.

1.
3 The movement of microscopic particles conforms to statistical laws

For microscopic particles, it is impossible to measure their spatial position and momentum at the same time
.

Therefore, the method of studying the movement of macroscopic objects cannot be used to study the movement of microscopic particles

Figure 5-1 Schematic diagram of electron diffraction experiment

The volatility of electrons is the result of particle statistics.

The movement of a single microscopic particle is irregular, but the result of statistics is regular, and the movement of microscopic particles can be studied with statistical laws