# CHGate¶

class CHGate(label=None, ctrl_state=None)[소스]

기반 클래스: qiskit.circuit.controlledgate.ControlledGate

Applies a Hadamard on the target qubit if the control is in the $$|1\rangle$$ state.

Circuit symbol:

q_0: ──■──
┌─┴─┐
q_1: ┤ H ├
└───┘


Matrix Representation:

$\begin{split}CH\ q_0, q_1 = I \otimes |0\rangle\langle 0| + H \otimes |1\rangle\langle 1| = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & \frac{1}{\sqrt{2}} & 0 & \frac{1}{\sqrt{2}} \\ 0 & 0 & 1 & 0 \\ 0 & \frac{1}{\sqrt{2}} & 0 & -\frac{1}{\sqrt{2}} \end{pmatrix}\end{split}$

참고

In Qiskit’s convention, higher qubit indices are more significant (little endian convention). In many textbooks, controlled gates are presented with the assumption of more significant qubits as control, which in our case would be q_1. Thus a textbook matrix for this gate will be:

     ┌───┐
q_0: ┤ H ├
└─┬─┘
q_1: ──■──

$\begin{split}CH\ q_1, q_0 = |0\rangle\langle 0| \otimes I + |1\rangle\langle 1| \otimes H = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & \frac{1}{\sqrt{2}} & \frac{1}{\sqrt{2}} \\ 0 & 0 & \frac{1}{\sqrt{2}} & -\frac{1}{\sqrt{2}} \end{pmatrix}\end{split}$

Create new CH gate.

Methods Defined Here

 inverse Return inverted CH gate (itself).

Attributes

ctrl_state

Return the control state of the gate as a decimal integer.

반환 형식

int

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

Return definition in terms of other basic gates. If the gate has open controls, as determined from self.ctrl_state, the returned definition is conjugated with X without changing the internal _definition.

반환 형식

List

duration

Get the duration.

label

Return instruction label

반환 형식

str

name

Get name of gate. If the gate has open controls the gate name will become:

<original_name_o<ctrl_state>

where <original_name> is the gate name for the default case of closed control qubits and <ctrl_state> is the integer value of the control state for the gate.

반환 형식

str

num_ctrl_qubits

Get number of control qubits.

반환값

The number of control qubits for the gate.

반환 형식

int

params

Get parameters from base_gate.

반환값

List of gate parameters.

반환 형식

list

예외

CircuitError – Controlled gate does not define a base gate

unit

Get the time unit of duration.