2017/02/28 by Aditya Jain, Indranil Chakrabarty, Sourav Chatterjee
Computer Science · Mathematics · Physics and Astronomy · #Algorithm #Broadcasting (networking) #Cloning (programming) #Combinatorics #Computer network #Computer science #Mathematics #Pauli exclusion principle #Physics #Political science #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum channel #Quantum cloning #Quantum entanglement #Quantum mechanics #State (computer science) #Teleportation #Theoretical computer science #Topology (electrical circuits) #Unitary state #quant-ph
paper · pdf · doi:10.1103/physreva.99.022315
published as Phys. Rev. A 99, 022315 (2019) · Edited sections, changed figures, to be published in Physical Review A
arxiv created 2019/01/11 · openalex publication_date 2019/02/13 · arxiv updated 2019/02/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In this work, we exhaustively investigate 1\ensuremath→2 local and nonlocal broadcasting of entanglement as well as correlations beyond entanglement (geometric discord) using asymmetric Pauli cloners with the most general two-qubit state as the resource. We exemplify asymmetric broadcasting of entanglement using ``maximally entangled mixed states.'' We demonstrate the variation of broadcasting range with the amount of entanglement present in the resource state as well as with the asymmetry in the cloner. We show that it is impossible to optimally broadcast geometric discord with the help of these asymmetric Pauli cloning machines. We also study the problem of 1\ensuremath→3 broadcasting of entanglement using nonmaximally entangled state as the resource. For this task, we introduce a method we call successive broadcasting which involves application of 1\ensuremath→2 optimal cloning machines multiple times. We compare and contrast the performance of this method with the application of direct 1\ensuremath→3 optimal cloning machines. We show that 1\ensuremath→3 optimal cloner does a better job at broadcasting than the successive application of 1\ensuremath→2 cloners and the successive method can be beneficial in the absence of 1\ensuremath→3 cloners. We also bring out the fundamental difference between the tasks of cloning and broadcasting in the final part of the paper. We create examples to show that there exist local unitaries which can be employed to give a better range for broadcasting. Such unitary operations are not only economical, but also surpass the best possible range obtained using existing cloning machines enabling broadcasting of lesser entangled states. This result opens up a direction in exploration of methods to facilitate broadcasting which may outperform the standard strategies implemented through cloning transformations.