# cirq.S¶

cirq.S = cirq.S

A gate that rotates around the Z axis of the Bloch sphere.

The unitary matrix of ZPowGate(exponent=t) is:

[[1, 0],
[0, g]]


where:

g = exp(i·π·t).

Note in particular that this gate has a global phase factor of
e^{i·π·t/2} vs the traditionally defined rotation matrices
about the Pauli Z axis. See cirq.Rz for rotations without the global
phase. The global phase factor can be adjusted by using the global_shift
parameter when initializing.

cirq.Z, the Pauli Z gate, is an instance of this gate at exponent=1.