---
title: plot_state_paulivec (v1.0)
description: API reference for qiskit.visualization.plot_state_paulivec in qiskit v1.0
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/1.0/qiskit.visualization.plot_state_paulivec
---

# qiskit.visualization.plot\_state\_paulivec

`qiskit.visualization.plot_state_paulivec(state, title='', figsize=None, color=None, ax=None, *, filename=None)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/1.0/qiskit/utils/lazy_tester.py#L610-L721)

Plot the Pauli-vector representation of a quantum state as bar graph.

The Pauli-vector of a density matrix $\rho$ is defined by the expectation of each possible tensor product of single-qubit Pauli operators (including the identity), that is

$$
\rho = \frac{1}{2^n} \sum_{\sigma \in \{I, X, Y, Z\}^{\otimes n}}
\mathrm{Tr}(\sigma \rho) \sigma.
$$

This function plots the coefficients $\mathrm{Tr}(\sigma\rho)$ as bar graph.

**Parameters**

- **state** ([*Statevector*](/docs/api/qiskit/1.0/qiskit.quantum_info.Statevector "qiskit.quantum_info.Statevector")  *or*[*DensityMatrix*](/docs/api/qiskit/1.0/qiskit.quantum_info.DensityMatrix "qiskit.quantum_info.DensityMatrix") *or ndarray*) – an N-qubit quantum state.
- **title** ([*str*](https://docs.python.org/3/library/stdtypes.html#str)) – a string that represents the plot title
- **figsize** ([*tuple*](https://docs.python.org/3/library/stdtypes.html#tuple)) – Figure size in inches.
- **color** ([*list*](https://docs.python.org/3/library/stdtypes.html#list)  *or*[*str*](https://docs.python.org/3/library/stdtypes.html#str)) – Color of the coefficient value bars.
- **ax** ([*matplotlib.axes.Axes*](https://matplotlib.org/stable/api/_as_gen/matplotlib.axes.Axes.html#matplotlib.axes.Axes "(in Matplotlib v3.8.4)")) – An optional Axes object to be used for the visualization output. If none is specified a new matplotlib Figure will be created and used. Additionally, if specified there will be no returned Figure since it is redundant.

**Returns**

The matplotlib.Figure of the visualization if the `ax` kwarg is not set

**Return type**

[`matplotlib.figure.Figure`](https://matplotlib.org/stable/api/figure_api.html#matplotlib.figure.Figure "(in Matplotlib v3.8.4)")

**Raises**

- [**MissingOptionalLibraryError**](/docs/api/qiskit/1.0/exceptions#qiskit.exceptions.MissingOptionalLibraryError "qiskit.exceptions.MissingOptionalLibraryError") – Requires matplotlib.
- [**VisualizationError**](/docs/api/qiskit/1.0/visualization#qiskit.visualization.VisualizationError "qiskit.visualization.VisualizationError") – if input is not a valid N-qubit state.

**Examples**

```python
# You can set a color for all the bars.

from qiskit import QuantumCircuit
from qiskit.quantum_info import Statevector
from qiskit.visualization import plot_state_paulivec

qc = QuantumCircuit(2)
qc.h(0)
qc.cx(0, 1)

state = Statevector(qc)
plot_state_paulivec(state, color='midnightblue', title="New PauliVec plot")
```

![../\_images/qiskit-visualization-plot\_state\_paulivec-1.png](https://eu-de.quantum.cloud.ibm.com/docs/images/api/qiskit/1.0/qiskit-visualization-plot_state_paulivec-1.avif)

```python
# If you introduce a list with less colors than bars, the color of the bars will
# alternate following the sequence from the list.

import numpy as np
from qiskit.quantum_info import DensityMatrix
from qiskit import QuantumCircuit
from qiskit.visualization import plot_state_paulivec

qc = QuantumCircuit(2)
qc.h(0)
qc.cx(0, 1)

qc = QuantumCircuit(2)
qc.h([0, 1])
qc.cz(0, 1)
qc.ry(np.pi/3, 0)
qc.rx(np.pi/5, 1)

matrix = DensityMatrix(qc)
plot_state_paulivec(matrix, color=['crimson', 'midnightblue', 'seagreen'])
```

![../\_images/qiskit-visualization-plot\_state\_paulivec-2.png](https://eu-de.quantum.cloud.ibm.com/docs/images/api/qiskit/1.0/qiskit-visualization-plot_state_paulivec-2.avif)