Amar Vutha of the University of Toronto in Canada explains this: Quantum computers, quantum cryptography and quantum-related things are often reported in the news. Articles about them will inevitably mention entanglement, and the essence of quantum physics makes these magical devices come true.
Einstein called entanglement "ghostly action at a distance", and this name was gradually understood by people. Besides building quantum computers, it is also very useful to understand and use entanglement in other ways. For example, it can be used to measure gravitational waves to obtain more accurate data, so that we can better understand the properties of special materials. It can also be revealed more accurately in other fields: I have been studying how particles collide with each other to form entanglement, and I want to know how it affects the accuracy of atomic clocks.
The law of conservation is the most common and important concept in all physics. The law of conservation of energy means that the total energy of a closed (isolated) system remains unchanged (it can be converted into other energy such as electric energy, mechanical energy or thermal energy). This law is the foundation of all our machines, whether steam engines or trams. The law of conservation is like an accounting book: you can change a small amount of energy around you, but the total amount must be the same.
The conservation of momentum (momentum is mass times speed) can explain that two skaters with different weights push away from each other, and the lighter one can skate faster and farther. This law also explains the famous adage: for every force, there is an equal and opposite reaction. (Take the skater as an example again) The conservation of angular kinetic energy explains that a rotating skater can approach her faster by grasping her arm.
French figure skaters Gabriella Papadakis and Guillaume Cizeron held the European Figure Skating Championships in Belarus in 20 19, which proved the influence of conservation law. These conservation laws have been proved by experiments, and they all work in a wide range of the universe, from black holes in distant galaxies to the smallest rotating electrons.
Imagine yourself having a wonderful hiking in the forest. You meet a fork in the road, but you can't decide whether to go left or right. The path leading to the left is dark, but there is a beautiful scenery at the end; The path on the right is sunny but rugged. You finally decided to go right, but you still cling to the road on the left. In the quantum world, you can choose any way. For quantum mechanical systems (in which everything is completely separated from high temperature and external disturbances), the laws inside are even more interesting. For example, like a spinning top, atoms can keep rotating clockwise or counterclockwise. Although it is different from the spinning top, it can still keep the state of 【 clockwise rotation 】+【 counterclockwise rotation 】. Quantum systems can be added or subtracted. Mathematically speaking, the combination rule of quantum states can also be described as the addition and subtraction rule of vectors. For such a combination of quantum states, the world is superimposed. Behind the strange quantum effect, you may have heard of the double-slit experiment or the wave-particle duality.