CZ Gate The CZ gate (or CPhase gate) is two-qubit operation defined as: CZ=(100001000010000−1)\ CZ = \begin{pmatrix} 1 & 0 & 0 & 0 \ 0 & 1 & 0 & 0 \ 0 & 0 & 1 & 0 \ 0 & 0 & 0 & -1 \end{pmatrix} CZ=⎝⎜⎜⎛100001000010000−1⎠⎟⎟⎞