= Clifford gates
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This gate set alone is not a set of <universal quantum gates>.
Notably, circuits containing those gates alone can be fully simulated by classical computers according to the <Gottesman-Knill theorem>, so there's no way they could be universal.
This means that if we add any number of Clifford gates to a quantum circuit, we haven't really increased the complexity of the algorithm, which can be useful as a transformational device.
A popular set of <universal quantum gates> derived from <Clifford gates> is <Clifford plus T>.