2016/12/31 by Fabian Steinlechner, Sebastian Ecker, Matthias Fink +5 · 2 citations
Computer Science · Engineering · Physics and Astronomy · #Amplitude damping channel #Multipartite entanglement #Optical Wireless Communication Technologies #Orbital Angular Momentum in Optics #Quantum Information and Cryptography #Quantum capacity #Quantum channel #Quantum discord #Quantum entanglement #Quantum key distribution #Quantum sensor #Squashed entanglement #W state #quant-ph
paper · pdf · doi:10.1038/ncomms15971
published as Nature Communications 8, 15971 (2017)
openalex created_date 2016/12/16 · openalex publication_date 2017/07/24 · arxiv created 2017/08/22 · arxiv updated 2017/08/23 · openalex updated_date 2026/08/06
Quantum entanglement is a fundamental resource in quantum information processing and its distribution between distant parties is a key challenge in quantum communications. Increasing the dimensionality of entanglement has been shown to improve robustness and channel capacities in secure quantum communications. Here we report on the distribution of genuine high-dimensional entanglement via a 1.2-km-long free-space link across Vienna. We exploit hyperentanglement, that is, simultaneous entanglement in polarization and energy-time bases, to encode quantum information, and observe high-visibility interference for successive correlation measurements in each degree of freedom. These visibilities impose lower bounds on entanglement in each subspace individually and certify four-dimensional entanglement for the hyperentangled system. The high-fidelity transmission of high-dimensional entanglement under real-world atmospheric link conditions represents an important step towards long-distance quantum communications with more complex quantum systems and the implementation of advanced quantum experiments with satellite links.