Optimal implementation of quantum gates with two controls
Jens Palsberg, Nengkun Yu · Linear Algebra and its Applications · 2024
We give a detailed proof of a well-known theorem in quantum computing. The theorem characterizes the number of two-qubit gates that is necessary for implementing three-qubit quantum gates with two controls. For example, the theorem implies that five 2-qubit gates are necessary for implementing the Toffoli gate. No detailed proof was available earlier.