ZGate

class qiskit.circuit.library.ZGate(label=None)

Bases: Gate

The single-qubit Pauli-Z gate ( $\sigma_z$ ).

Can be applied to a QuantumCircuit with the z() method.

Matrix Representation:

\begin{split}Z = \begin{pmatrix} 1 & 0 \\ 0 & -1 \end{pmatrix}\end{split}

Circuit symbol:

     ┌───┐
q_0: ┤ Z ├
     └───┘

Equivalent to a $\pi$ radian rotation about the Z axis.

Note

A global phase difference exists between the definitions of $RZ(\pi)$ and $Z$ .

\begin{split}RZ(\pi) = \begin{pmatrix} -i & 0 \\ 0 & i \end{pmatrix} = -i Z\end{split}

The gate is equivalent to a phase flip.

\begin{split}|0\rangle \rightarrow |0\rangle \\ |1\rangle \rightarrow -|1\rangle\end{split}

Create new Z gate.

Attributes

condition_bits

Get Clbits in condition.

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

name

Return the name.

num_clbits

Return the number of clbits.

num_qubits

Return the number of qubits.

params

return instruction params.

unit

Get the time unit of duration.

Methods

control

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

Return a (multi-)controlled-Z gate.

One control returns a CZ 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 orstr 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

inverse()

Return inverted Z gate (itself).

power

power(exponent)

Raise gate to a power.

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