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Fundamental limits of repeaterless quantum communications
Stefano Pirandola1, Riccardo Laurenza1, Carlo Ottaviani1
1Department of Computer Science and York Centre for Quantum Technologies, University of York, York YO10 5GH, UK.
Nature Communications
|April 27, 2017
Summary
This study determines the ultimate rates for quantum communication without repeaters, establishing fundamental limits for secure key distribution and entanglement sharing across various quantum channels.
Area of Science:
- Quantum Information Science
- Quantum Communication Theory
Background:
- Quantum communication aims for secure information transmission, entanglement distribution, and key generation.
- Determining optimal point-to-point rates is crucial for these applications, especially without quantum repeaters.
Purpose of the Study:
- Establish the ultimate achievable rates for two-way assisted quantum communication channels.
- Define fundamental limits for quantum key distribution protocols.
Main Methods:
- Constructing an upper bound using the relative entropy of entanglement.
- Devising a dimension-independent technique called 'teleportation stretching'.
Main Results:
- Capacities determined for bosonic lossy, quantum-limited amplifier, dephasing, and erasure channels in arbitrary dimensions.
- Exact characterization of the fundamental rate-loss tradeoff in quantum key distribution.
Conclusions:
- The findings set definitive limits for point-to-point quantum communication.
- Provides precise benchmarks for the development of quantum repeaters.
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