qiskit-documentation/docs/api/qiskit/0.32/qiskit.circuit.library.U2Ga...

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---
title: U2Gate
description: API reference for qiskit.circuit.library.U2Gate
in_page_toc_min_heading_level: 1
python_api_type: class
python_api_name: qiskit.circuit.library.U2Gate
---
# U2Gate
<Class id="qiskit.circuit.library.U2Gate" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.18/qiskit/circuit/library/standard_gates/u2.py" signature="U2Gate(phi, lam, label=None)" modifiers="class">
Bases: `qiskit.circuit.gate.Gate`
Single-qubit rotation about the X+Z axis.
Implemented using one X90 pulse on IBM Quantum systems:
$$
U2(\phi, \lambda) = RZ(\phi).RY(\frac{\pi}{2}).RZ(\lambda)
$$
**Circuit symbol:**
```python
┌─────────┐
q_0: ┤ U2(φ,λ) ├
└─────────┘
```
**Matrix Representation:**
$$
\begin{split}U2(\phi, \lambda) = \frac{1}{\sqrt{2}}
\begin{pmatrix}
1 & -e^{i\lambda} \\
e^{i\phi} & e^{i(\phi+\lambda)}
\end{pmatrix}\end{split}
$$
**Examples:**
$$
U2(0, \pi) = H
U2(0, 0) = RY(\pi/2)
U2(-\pi/2, \pi/2) = RX(\pi/2)
$$
<Admonition title="See also" type="note">
`U3Gate`: U3 is a generalization of U2 that covers all single-qubit rotations, using two X90 pulses.
</Admonition>
Create new U2 gate.
## Methods Defined Here
### inverse
<Function id="qiskit.circuit.library.U2Gate.inverse" signature="U2Gate.inverse()">
Return inverted U2 gate.
$U2(\phi, \lambda)^{\dagger} =U2(-\lambda-\pi, -\phi+\pi)$)
</Function>
## Attributes
### decompositions
<Attribute id="qiskit.circuit.library.U2Gate.decompositions">
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
</Attribute>
### definition
<Attribute id="qiskit.circuit.library.U2Gate.definition">
Return definition in terms of other basic gates.
</Attribute>
### duration
<Attribute id="qiskit.circuit.library.U2Gate.duration">
Get the duration.
</Attribute>
### label
<Attribute id="qiskit.circuit.library.U2Gate.label">
Return instruction label
**Return type**
`str`
</Attribute>
### params
<Attribute id="qiskit.circuit.library.U2Gate.params">
return instruction params.
</Attribute>
### unit
<Attribute id="qiskit.circuit.library.U2Gate.unit">
Get the time unit of duration.
</Attribute>
</Class>