Monday, July 19, 2021

Quantum Computing for Beginners

There are three important properties of quantum mechanics:

Superposition, Entanglement, and Interferences 

Superposition

For colors, b/w has 2 colors, gif has 256 colors, same as VGA (2^8), SVGA has 2^16=65536 colors, true color (24bit) has 2^24 = 16 million, deep color has 2^30 = 1 billon colors. Now we are using digital computer. The binary system has two numbers 0 and 1. So we are at b/w stage. 

For music, bugle has 5 notes (or may be three), march/pop songs/national anthem uses mostly 7 notes, opera/orchestra/Mozart uses 12 notes. As we know, orchestra has more details and rich melody than bugles. You can consider using a digital computer is kind of listening bugle instead of orchestra music. 

The superposition property enables quantum computers to represent more information in each unit (qubit) therefore a vast amount of data can be processed in one step. 

Entanglement

We know that twin brothers or sisters can somehow "communicate" even though they are physically apart. It seems there is something (or someone) that sends information between each other. 

Players in Matching bands synchronize with the conductor. This means, one move, all follows. 

The entanglement property "sends" information from one particle to another without delay. It seems there is a super force (God?) to control the particles' rotations with the identical angles along XYZ axes. Once entangled, one can control all qubits by just manipulating one qubit. (The others will follow). It functions like a lever. 

Interferences

Throwing two rocks in still water you will see waves and when two waves meet, they add or cancel base on the phases of the waves. 

A clock (minute hand) is a good example to explain phases. 12 o'clock is considered phase = 0, at 5 minute phase = 15 (degree), at 15 minute phase = 90. After one hour, the minute hand goes back to phase =0.

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Summary

Entangled qubits have a vast number of different phases (considering distributing on a clock), most of them cancel each other (eg. 5 minute and 35 minute cancel each other). Some add up (remember waves). In the end, a few that with same phase become much larger (fit) than the rest. They are the solutions to the problem. 

If you know genetic algorithm or evolutionary computation, it functions similar, same is true comparing to the human evolution. The fit species remain and get better (more fit). Unfit species disappear.

[This explanation uses a form of story teller rather than Einstein level scientific definitions and quantum theory.]