56 lines
2.6 KiB
Plaintext
56 lines
2.6 KiB
Plaintext
---
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title: plot_state_qsphere
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description: API reference for qiskit.visualization.plot_state_qsphere
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in_page_toc_min_heading_level: 1
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python_api_type: function
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python_api_name: qiskit.visualization.plot_state_qsphere
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---
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# qiskit.visualization.plot\_state\_qsphere
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<Function id="qiskit.visualization.plot_state_qsphere" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.18/qiskit/visualization/state_visualization.py" signature="plot_state_qsphere(state, figsize=None, ax=None, show_state_labels=True, show_state_phases=False, use_degrees=False, *, rho=None)">
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Plot the qsphere representation of a quantum state. Here, the size of the points is proportional to the probability of the corresponding term in the state and the color represents the phase.
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**Parameters**
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* **state** ([*Statevector*](qiskit.quantum_info.Statevector "qiskit.quantum_info.Statevector") *or*[*DensityMatrix*](qiskit.quantum_info.DensityMatrix "qiskit.quantum_info.DensityMatrix") *or ndarray*) – an N-qubit quantum state.
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* **figsize** (*tuple*) – Figure size in inches.
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* **ax** (*matplotlib.axes.Axes*) – 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.
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* **show\_state\_labels** (*bool*) – An optional boolean indicating whether to show labels for each basis state.
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* **show\_state\_phases** (*bool*) – An optional boolean indicating whether to show the phase for each basis state.
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* **use\_degrees** (*bool*) – An optional boolean indicating whether to use radians or degrees for the phase values in the plot.
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**Returns**
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A matplotlib figure instance if the `ax` kwarg is not set
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**Return type**
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Figure
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**Raises**
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* [**MissingOptionalLibraryError**](qiskit.aqua.MissingOptionalLibraryError "qiskit.aqua.MissingOptionalLibraryError") – Requires matplotlib.
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* [**VisualizationError**](qiskit.visualization.VisualizationError "qiskit.visualization.VisualizationError") – if input is not a valid N-qubit state.
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* **QiskitError** – Input statevector does not have valid dimensions.
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**Example**
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```python
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from qiskit import QuantumCircuit
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from qiskit.quantum_info import Statevector
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from qiskit.visualization import plot_state_qsphere
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%matplotlib inline
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qc = QuantumCircuit(2)
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qc.h(0)
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qc.cx(0, 1)
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state = Statevector.from_instruction(qc)
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plot_state_qsphere(state)
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```
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</Function>
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