1,205 research outputs found
Strong connections between quantum encodings, non-locality and quantum cryptography
Encoding information in quantum systems can offer surprising advantages but
at the same time there are limitations that arise from the fact that measuring
an observable may disturb the state of the quantum system. In our work, we
provide an in-depth analysis of a simple question: What happens when we perform
two measurements sequentially on the same quantum system? This question touches
upon some fundamental properties of quantum mechanics, namely the uncertainty
principle and the complementarity of quantum measurements. Our results have
interesting consequences, for example they can provide a simple proof of the
optimal quantum strategy in the famous Clauser-Horne-Shimony-Holt game.
Moreover, we show that the way information is encoded in quantum systems can
provide a different perspective in understanding other fundamental aspects of
quantum information, like non-locality and quantum cryptography. We prove some
strong equivalences between these notions and provide a number of applications
in all areas.Comment: Version 3. Previous title: "Oblivious transfer, the CHSH game, and
quantum encodings
Oblivious transfer and quantum channels
We show that oblivious transfer can be seen as the classical analogue to a
quantum channel in the same sense as non-local boxes are for maximally
entangled qubits.Comment: Invited Paper at the 2006 IEEE Information Theory Workshop (ITW 2006
Tsirelson's Bound Prohibits Communication Through a Disconnected Channel
Why does nature only allow nonlocal correlations up to Tsirelson's bound and
not beyond? We construct a channel whose input is statistically independent of
its output, but through which communication is nevertheless possible if and
only if Tsirelson's bound is violated. This provides a statistical
justification for Tsirelson's bound on nonlocal correlations in a bipartite
setting.Comment: 9 pages, 2 figures. Title and abstract modified, exposition
simplifie
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