  The prime objective of this study is to seek a circuit diagram for a
multi-inputs Toffoli gate including only single qubit gates and CNOTs. In this
regard, we have developed two variational quantum algorithms that can be used
to implement a multi-inputs Toffoli gate. The cost functions of these two VQAs
are derived by using the Hilbert Schmidt inner product and the expected value
of an observable that can capture the difference between the inputs and outputs
of a Toffoli gate. We employ two ansatz circuit architectures and use the
PennyLane package to execute the optimization.
