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SwapGate

class SwapGate(label=None)

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Bases: qiskit.circuit.gate.Gate

The SWAP gate.

This is a symmetric and Clifford gate.

Circuit symbol:

q_0: ─X─

q_1: ─X─

Matrix Representation:

SWAP=(1000001001000001)\begin{split}SWAP = \begin{pmatrix} 1 & 0 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 0 & 1 \end{pmatrix}\end{split}

The gate is equivalent to a state swap and is a classical logic gate.

a,bb,a|a, b\rangle \rightarrow |b, a\rangle

Create new SWAP gate.


Methods Defined Here

control

SwapGate.control(num_ctrl_qubits=1, label=None, ctrl_state=None)

Return a (multi-)controlled-SWAP gate.

One control returns a CSWAP (Fredkin) gate.

Parameters

  • num_ctrl_qubits (int) – number of control qubits.
  • label (str or None) – An optional label for the gate [Default: None]
  • ctrl_state (int or str or None) – control state expressed as integer, string (e.g. ‘110’), or None. If None, use all 1s.

Returns

controlled version of this gate.

Return type

ControlledGate

inverse

SwapGate.inverse()

Return inverse Swap gate (itself).


Attributes

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

Return definition in terms of other basic gates.

duration

Get the duration.

label

Return instruction label

Return type

str

params

return instruction params.

unit

Get the time unit of duration.

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