Phys.org June 3, 2019
To fully understand the fundamental laws that prevent quantum communications to simultaneously achieve high rates and long distances, an international team of researchers (UK, USA – MIT) derived single-letter upper bounds for the end-to-end capacities achievable by the most general (adaptive) protocols of quantum and private communication, from a single repeater chain to an arbitrarily complex quantum network, where systems may be routed through single or multiple paths. They analytically established these capacities under fundamental noise models, including bosonic loss which is the most important for optical communications. The results provide the ultimate benchmarks for testing the optimal performance of repeater-assisted quantum communications…read more. Open Access TECHNICAL ARTICLE
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