CR gate

The CR gate is a controlled phase shift with angle $\theta$ (radians), defined by:

$\ CR = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 0 & 0 & e^{\theta i} \end{pmatrix}$

This gate is a generalization of the CZ gate.