proj_choi_to_unitary

forest.benchmarking.operator_tools.project_superoperators.proj_choi_to_unitary(choi: numpy.ndarray, check_finite: bool = True) → numpy.ndarray

Compute the unitary closest to a quantum process specified by a Choi matrix.

This function enforces Hermiticity of the Choi matrix. See [IntQC] for more details:

[IntQC]

Interference of Quantum Channels. Daniel K. L. Oi. Phys. Rev. Lett. 91, 067902 (2003). https://doi.org/10.1103/PhysRevLett.91.067902 https://arxiv.org/abs/quant-ph/0303178

Parameters:

• choi – the Choi representation of a quantum process.
• check_finite – check that the input matrices contain only finite numbers.

Returns:

choi matrix corresponding to the closest unitary