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Tutorial with basic notion of error correction in the classical domain, including the connection between classical coding theory and the quantum coding theory.
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What are the ultimate limits that nature imposes on communication and what are effective procedures for achieving these limits?
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Dr. Winter and collegues have recently defined the locking capacity of a quantum channel as the largest rate of a uniformly distributed bit string, which Alice can share with Bob over the channel while an eavesdropper, Eve, who has access to the channel environment, can only gain negligible accessible information about the string. We show that this relaxation of the private capacity of a channel, can be much larger than the latter; in fact, if a sub-linear size key is shared between Alice and Bob, there are channels with zero private capacity but positive locking capacity. This gives a quantitative meaning to the information locking effect [DiVincenzo et al., PRL 92:067902, 2004], and answers an open question of Guha et al. [Based on arXiv:1403.6361, J Cryptol 2017].
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In this talk, we describe some of ORNL’s most recent and ongoing work in quantum communications. In the first part of the talk, we will focus on quantum approaches to improve cybersecurity. In the second part of the talk, we will describe recent quantum networking experiments and finish by looking to a future where quantum repeaters enable continental-scale quantum communications.
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Quantum physics has the potential to significantly outperform classical techniques in areas such as computing, sensing, and communications. Here we show a quantum communication protocol called floodlight quantum key distribution that can outperform standard techniques by breaking conventional rules of operation, including sending many photons per bit duration and use of an amplifier to mitigate channel loss. In a tabletop experiment, we have achieved Gbps secret-key rates in a 10-dB-loss transmission channel, showing 3 orders of magnitude improvement over other quantum protocols.
