C贸digo fuente para qiskit.circuit.library.standard_gates.ryy

# This code is part of Qiskit.
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# (C) Copyright IBM 2017, 2020.
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"""Two-qubit YY-rotation gate."""
import math
from typing import Optional
import numpy as np
from qiskit.circuit.gate import Gate
from qiskit.circuit.quantumregister import QuantumRegister
from qiskit.circuit.parameterexpression import ParameterValueType


[documentos]class RYYGate(Gate): r"""A parametric 2-qubit :math:`Y \otimes Y` interaction (rotation about YY). This gate is symmetric, and is maximally entangling at :math:`\theta = \pi/2`. Can be applied to a :class:`~qiskit.circuit.QuantumCircuit` with the :meth:`~qiskit.circuit.QuantumCircuit.ryy` method. **Circuit Symbol:** .. parsed-literal:: 鈹屸攢鈹鈹鈹鈹鈹鈹鈹鈹鈹 q_0: 鈹1 鈹 鈹 Ryy(洗) 鈹 q_1: 鈹0 鈹 鈹斺攢鈹鈹鈹鈹鈹鈹鈹鈹鈹 **Matrix Representation:** .. math:: \newcommand{\th}{\frac{\theta}{2}} R_{YY}(\theta) = \exp\left(-i \th Y{\otimes}Y\right) = \begin{pmatrix} \cos\left(\th\right) & 0 & 0 & i\sin\left(\th\right) \\ 0 & \cos\left(\th\right) & -i\sin\left(\th\right) & 0 \\ 0 & -i\sin\left(\th\right) & \cos\left(\th\right) & 0 \\ i\sin\left(\th\right) & 0 & 0 & \cos\left(\th\right) \end{pmatrix} **Examples:** .. math:: R_{YY}(\theta = 0) = I .. math:: R_{YY}(\theta = \pi) = i Y \otimes Y .. math:: R_{YY}\left(\theta = \frac{\pi}{2}\right) = \frac{1}{\sqrt{2}} \begin{pmatrix} 1 & 0 & 0 & i \\ 0 & 1 & -i & 0 \\ 0 & -i & 1 & 0 \\ i & 0 & 0 & 1 \end{pmatrix} """ def __init__(self, theta: ParameterValueType, label: Optional[str] = None): """Create new RYY gate.""" super().__init__("ryy", 2, [theta], label=label) def _define(self): """Calculate a subcircuit that implements this unitary.""" # pylint: disable=cyclic-import from qiskit.circuit.quantumcircuit import QuantumCircuit from .x import CXGate from .rx import RXGate from .rz import RZGate # 鈹屸攢鈹鈹鈹鈹鈹鈹鈹鈹鈹 鈹屸攢鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹 # q_0: 鈹 Rx(蟺/2) 鈹溾攢鈹鈻犫攢鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈻犫攢鈹鈹 Rx(-蟺/2) 鈹 # 鈹溾攢鈹鈹鈹鈹鈹鈹鈹鈹鈹も攲鈹鈹粹攢鈹愨攲鈹鈹鈹鈹鈹鈹鈹鈹愨攲鈹鈹粹攢鈹愨敎鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹 # q_1: 鈹 Rx(蟺/2) 鈹溾敜 X 鈹溾敜 Rz(0) 鈹溾敜 X 鈹溾敜 Rx(-蟺/2) 鈹 # 鈹斺攢鈹鈹鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹樷敂鈹鈹鈹鈹鈹鈹鈹鈹樷敂鈹鈹鈹鈹樷敂鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹鈹 q = QuantumRegister(2, "q") theta = self.params[0] qc = QuantumCircuit(q, name=self.name) rules = [ (RXGate(np.pi / 2), [q[0]], []), (RXGate(np.pi / 2), [q[1]], []), (CXGate(), [q[0], q[1]], []), (RZGate(theta), [q[1]], []), (CXGate(), [q[0], q[1]], []), (RXGate(-np.pi / 2), [q[0]], []), (RXGate(-np.pi / 2), [q[1]], []), ] for instr, qargs, cargs in rules: qc._append(instr, qargs, cargs) self.definition = qc
[documentos] def inverse(self): """Return inverse RYY gate (i.e. with the negative rotation angle).""" return RYYGate(-self.params[0])
def __array__(self, dtype=None): """Return a numpy.array for the RYY gate.""" theta = float(self.params[0]) cos = math.cos(theta / 2) isin = 1j * math.sin(theta / 2) return np.array( [[cos, 0, 0, isin], [0, cos, -isin, 0], [0, -isin, cos, 0], [isin, 0, 0, cos]], dtype=dtype, )
[documentos] def power(self, exponent: float): """Raise gate to a power.""" (theta,) = self.params return RYYGate(exponent * theta)