Four-qubit gates

Four-qubit gates in qoqo/roqoqo represent atomic instructions of any quantum computer that act on gour qubits. In three-qubit gates the qubits are referred to as control_0, control_1, control_2 and target. For four-qubit gates, the created matrix is always a 16x16-dimensional matrix. This convention corresponds to the little-endian encoding as described in chapter conventions. The full matrix form of the four-qubit gates implemented in qoqo/roqoqo is documented in this chapter.

The given form of the unitary matrix is consistent with the following ordering of qubit states in a four-qubit state space:

\[ \left|0000 \right> = \textrm{state} 0 \\ \left|0001 \right> = \textrm{state} 1 \\ \left|0010 \right> = \textrm{state} 2 \\ \left|0011 \right> = \textrm{state} 3 \\ \left|0100 \right> = \textrm{state} 4 \\ \left|0101 \right> = \textrm{state} 5 \\ \left|0110 \right> = \textrm{state} 6 \\ \left|0111 \right> = \textrm{state} 7 \\ \left|1000 \right> = \textrm{state} 8 \\ \left|1001 \right> = \textrm{state} 9 \\ \left|1010 \right> = \textrm{state} 10 \\ \left|1011 \right> = \textrm{state} 11 \\ \left|1100 \right> = \textrm{state} 12 \\ \left|1101 \right> = \textrm{state} 13 \\ \left|1110 \right> = \textrm{state} 14 \\ \left|1111 \right> = \textrm{state} 15 \\ \]

TripleControlledPauliX

The triple-controlled PauliX gate.

TripleControlledPauliZ

The triple-controlled PauliZ gate.

TripleControlledPhaseShift

The triple-controlled PhaseShift gate.