arXiv:1209.0449quant-ph
Classical command of quantum systems via rigidity of CHSH games
Abstract
Can a classical system command a general adversarial quantum system to realize arbitrary quantum dynamics? If so, then we could realize the dream of device-independent quantum cryptography: using untrusted quantum devices to establish a shared random key, with security based on the correctness of quantum mechanics. It would also allow for testing whether a claimed quantum computer is truly quantum. Here we report a technique by which a classical system can certify the joint, entangled state of a bipartite quantum system, as well as command the application of specific operators on each subsystem. This is accomplished by showing a strong converse to Tsirelson's optimality result for the Clauser-Horne-Shimony-Holt (CHSH) game: the only way to win many games is if the bipartite state is close to the tensor product of EPR states, and the measurements are the optimal CHSH measurements on successive qubits. This leads directly to a scheme for device-independent quantum key distribution. Control over the state and operators can also be leveraged to create more elaborate protocols for reliably realizing general quantum circuits.
This may not answer your question, but you might enjoy seeing how the 85.4% probability is derived in http://arxiv.org/pdf/1209.0448v1.pdf and http://arxiv.org/pdf/1209.0449v1.pdf
dj-wonkView on HNParent context
A note -- if you're linking to arXiv, it's better to link to the abstract (http://arxiv.org/abs/1209.0448, http://arxiv.org/abs/1209.0449) rather than directly to the PDF. From the abstract, one can easily click through to the PDF; not so the reverse. And the abstract allows one…
SniffnoyView on HNParent context