"""This module implements the ZZGate."""
from __future__ import annotations
import math
from bqskit.ir.gates.constantgate import ConstantGate
from bqskit.ir.gates.qubitgate import QubitGate
from bqskit.qis.unitary.unitarymatrix import UnitaryMatrix
[docs]
class ZZGate(ConstantGate, QubitGate):
"""
The Ising ZZ coupling gate.
The ZZ gate is given by the following unitary:
.. math::
\\begin{pmatrix}
\\frac{\\sqrt{2}}{2} - \\frac{\\sqrt{2}}{2}i & 0 & 0 & 0 \\\\
0 & \\frac{\\sqrt{2}}{2} + \\frac{\\sqrt{2}}{2}i & 0 & 0 \\\\
0 & 0 & \\frac{\\sqrt{2}}{2} + \\frac{\\sqrt{2}}{2}i & 0 \\\\
0 & 0 & 0 & \\frac{\\sqrt{2}}{2} - \\frac{\\sqrt{2}}{2}i \\\\
\\end{pmatrix}
"""
_num_qudits = 2
_qasm_name = 'rzz(pi/2)'
_utry = UnitaryMatrix(
[
[math.sqrt(2) / 2 - 1j * math.sqrt(2) / 2, 0, 0, 0],
[0, math.sqrt(2) / 2 + 1j * math.sqrt(2) / 2, 0, 0],
[0, 0, math.sqrt(2) / 2 + 1j * math.sqrt(2) / 2, 0],
[0, 0, 0, math.sqrt(2) / 2 - 1j * math.sqrt(2) / 2],
],
)