---
title: quantum_volume (v2.1)
description: API reference for qiskit.circuit.library.quantum_volume in qiskit v2.1
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/2.1/qiskit.circuit.library.quantum_volume
---

# qiskit.circuit.library.quantum\_volume

`qiskit.circuit.library.quantum_volume(num_qubits, depth=None, seed=None)`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.1/qiskit/circuit/library/quantum_volume.py#L133-L180)

A quantum volume model circuit.

The model circuits are random instances of circuits used to measure the Quantum Volume metric, as introduced in \[1].

The model circuits consist of layers of Haar random elements of SU(4) applied between corresponding pairs of qubits in a random bipartition.

This function is multithreaded and will launch a thread pool with threads equal to the number of CPUs by default. You can tune the number of threads with the `RAYON_NUM_THREADS` environment variable. For example, setting `RAYON_NUM_THREADS=4` would limit the thread pool to 4 threads.

**Parameters**

- **num\_qubits** ([*int*](https://docs.python.org/3/library/functions.html#int)) – The number qubits to use for the generated circuit.
- **depth** ([*int*](https://docs.python.org/3/library/functions.html#int) *| None*) – The number of layers for the generated circuit. If this is not specified it will default to `num_qubits` layers.
- **seed** ([*int*](https://docs.python.org/3/library/functions.html#int) *| np.random.Generator | None*) – An optional RNG seed used for generating the random SU(4) matrices used in the output circuit. This can be either an integer or a numpy generator. If an integer is specfied it must be an value between 0 and 2\*\*64 - 1.

**Return type**

[QuantumCircuit](/docs/api/qiskit/2.1/qiskit.circuit.QuantumCircuit "qiskit.circuit.QuantumCircuit")

**Reference Circuit:**

![Diagram illustrating the previously described circuit.](https://eu-de.quantum.cloud.ibm.com/docs/images/api/qiskit/2.1/qiskit-circuit-library-quantum_volume-1.avif)

**References:**

\[1] A. Cross et al. Validating quantum computers using randomized model circuits, Phys. Rev. A 100, 032328 (2019). [arXiv:1811.12926](https://arxiv.org/abs/1811.12926)