2017/04/12 by James Titchener, James G. Titchener, Markus Gräfe +6
Computer Science · Physics and Astronomy · #Neural Networks and Reservoir Computing #One-way quantum computer #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum computer #Quantum error correction #Quantum information #Quantum state #Quantum tomography #Qubit #Scalability #Set (abstract data type) #physics.optics #quant-ph
paper · pdf · doi:10.1038/s41534-018-0063-5
published as npj Quantum Information 4, 19 (2018) · 21 pages, 9 figures (includes supplementary material)
openalex created_date 2016/12/16 · arxiv created 2017/04/12 · openalex publication_date 2018/02/20 · arxiv updated 2018/04/12 · openalex updated_date 2026/08/05
Abstract Quantum information systems are on a path to vastly exceed the complexity of any classical device. The number of entangled qubits in quantum devices is rapidly increasing, and the information required to fully describe these systems scales exponentially with qubit number. This scaling is the key benefit of quantum systems, however it also presents a severe challenge. To characterize such systems typically requires an exponentially long sequence of different measurements, becoming highly resource demanding for large numbers of qubits. Here we propose and demonstrate a novel and scalable method for characterizing quantum systems based on expanding a multi-photon state to larger dimensionality. We establish that the complexity of this new measurement technique only scales linearly with the number of qubits, while providing a tomographically complete set of data without a need for reconfigurability. We experimentally demonstrate an integrated photonic chip capable of measuring two- and three-photon quantum states with statistical reconstruction fidelity of 99.71%.