CXGate¶
- class CXGate(label=None, ctrl_state=None)[소스]¶
기반 클래스:
qiskit.circuit.controlledgate.ControlledGate
Controlled-X gate.
Circuit symbol:
q_0: ──■── ┌─┴─┐ q_1: ┤ X ├ └───┘
Matrix representation:
\[\begin{split}CX\ q_0, q_1 = I \otimes |0\rangle\langle0| + X \otimes |1\rangle\langle1| = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 1 \\ 0 & 0 & 1 & 0 \\ 0 & 1 & 0 & 0 \end{pmatrix}\end{split}\]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: ┤ X ├ └─┬─┘ q_1: ──■──
\[\begin{split}CX\ q_1, q_0 = |0 \rangle\langle 0| \otimes I + |1 \rangle\langle 1| \otimes X = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 0 & 1 \\ 0 & 0 & 1 & 0 \end{pmatrix}\end{split}\]In the computational basis, this gate flips the target qubit if the control qubit is in the \(|1\rangle\) state. In this sense it is similar to a classical XOR gate.
\[`|a, b\rangle \rightarrow |a, a \oplus b\rangle`\]Create new CX gate.
Methods Defined Here
Return a controlled-X gate with more control lines.
Return inverted CX 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.
- 반환
The number of control qubits for the gate.
- 반환 형식
int
- params¶
Get parameters from base_gate.
- 반환
List of gate parameters.
- 반환 형식
list
- 예외 발생
CircuitError – Controlled gate does not define a base gate
- unit¶
Get the time unit of duration.