2013/08/14 by Alessandro Bisio, Giacomo Mauro D’Ariano, Giacomo Mauro D'Ariano +3 · 1 citation
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Artificial intelligence #Channel (broadcasting) #Combinatorics #Computer science #Dimension (graph theory) #Exponential function #Mathematics #Physics #Preprocessor #Pure mathematics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum cloning #Quantum error correction #Quantum mechanics #Qubit #Reduction (mathematics) #Telecommunications #Topology (electrical circuits) #Transformation (genetics) #Unitary state #Unitary transformation #quant-ph
paper · pdf · doi:10.1016/j.physleta.2014.04.042
published as Physics Letters A 378, p. 1797 (2014) · 14 pages, 2 figures
arxiv created 2013/08/14 · openalex publication_date 2014/04/28 · arxiv updated 2014/09/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We consider the general problem of the optimal transformation of N uses of (possibly different) unitary channels to a single use of another unitary channel in any finite dimension. We show how the optimal transformation can be fully parallelized, consisting in a preprocessing channel followed by a parallel action of all the N unitaries and a final postprocessing channel. Our techniques allow to achieve an exponential reduction in the number of the free parameters of the optimization problem making it amenable to an efficient numerical treatment. Finally, we apply our general results to find the analytical solution for special cases of interest like the cloning of qubit phase gates.