> Each operation adds a little bit of error to the quantity that is being processed. This could be the voltage in an electronic analog computer, or the state co

> Each operation adds a little bit of error to the quantity that is being processed. This could be the voltage in an electronic analog computer, or the state coefficients in a quantum computer. This brings us back to the Quantum threshold theorem, which says that it's possible to design a quantum computer so that you can perform as many operations as you like without accumulating additional error, as long as individual gates in the quantum computer have a bounded amount of error. This is one of the reasons why thinking of a quantum computer as "analog" will lead you astray. Quantum computers are more like classical digital computers than like analog computers.