US Patent 8957699 Efficient Toffoli state generation from low-fidelity single qubit magic states

Systems and methods are provided for generating a high-fidelity Toffoli state from a plurality of low-fidelity single qubit magic states. First and second qubits are prepared in a high-fidelity initial state. N target qubits are prepared in the single qubit magic state. A series of gates are performed on the qubits, such that the system is in a state ½|0001 . . . 0N+½|0101 . . . 0N+½|1001 . . . 0N+½|1111 . . . 1N. A parity check is performed on the N target qubits. The parity check provides at least a first measurement value. The first qubit, the second qubit, and the first target qubit are accepted as the Toffoli state if the measurement values assume the desired values.