Employing confidence polytopes for quantum channel tomography

In the current work, we generalize the approach of confidence polytopes, originally designed for quantum state tomography, to quantum process tomography. The resulting approach allows obtaining a confidence region in the polytope form for a Choi matrix of an unknown competently positive trace-preserving map (quantum channel). We also show how confidence polytopes can be employed for calculating confidence intervals for affine functions of density matrices of quantum states and Choi matrices of quantum channels by using linear programming tools. We also demonstrate the performance and scalability of the developed approach. The talk is based on the paper arXiv:2109.04734 (accepted in "New Journal of Physics" journal).