"""This module implements the ClockGate."""
from __future__ import annotations
import numpy as np
from bqskit.ir.gates.constantgate import ConstantGate
from bqskit.ir.gates.quditgate import QuditGate
from bqskit.qis.unitary.unitarymatrix import UnitaryMatrix
from bqskit.utils.typing import is_integer
[docs]
class ClockGate(ConstantGate, QuditGate):
"""
The one-qudit clock (Z) gate. This is a Weyl-Heisenberg gate.
The clock gate is given by the following formula:
.. math::
Z = \\sum_a \\exp(\\frac{2\\pi ai}{d}) |a\\rangle\\langle a|
where d is the number of levels (2 levels is a qubit,
3 levels is a qutrit, etc.)
References:
- https://arxiv.org/pdf/2302.07966.pdf
"""
_num_qudits = 1
[docs]
def __init__(self, radix: int = 3) -> None:
"""
Construct a ClockGate.
Args:
radix (int): The number of qudit levels (>=2). Defaults to
qutrits.
Raises:
ValueError: if radix < 2
"""
if not is_integer(radix):
raise TypeError(f'Expected integer for radix, got {type(radix)}.')
if radix < 2:
raise ValueError(f'Radix must be greater than 1, got {radix}.')
self._radix = radix
# Calculate unitary
diags = [np.exp(2j * np.pi * i / radix) for i in range(radix)]
self._utry = UnitaryMatrix(np.diag(diags), self.radixes)