This app was developed based on the description in Prof. Chris Bernhardt's book "Quantum Computing for Everyone". This Fredkin gate F(x,y,z) is equipped with several mirrors so that the billiard ball can be properly oriented. Also, appropriate delays are added to the paths so that the ball will collide when it should, and not when it does not. Here we can see the behavior of the two most complicated cases F(1,1,0) and F(1,1,1).
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- It is a reversible logic gate. That is, the input can be reached from the output.
- It is a universal logic gate. In other words, NOT, AND, and fan-out (input duplication function) can be created only with this Fredkin gate.
- The number of 1s (True) in input and output is always equal. This corresponds to the fact that the number of billiard balls, which will be described later, is always equal between the input side and the output side.