qiskit.circuit.library.quantum_volume

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

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) – The number qubits to use for the generated circuit.
• depth (int | None) – The number of layers for the generated circuit. If this is not specified it will default to num_qubits layers.
• seed (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

Reference Circuit:

References:

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