Quantum Cryptography as a Retrodiction Problem

Quantum cryptography as a retrodiction problem.

We propose a quantum key distribution protocol based on a quantum retrodiction protocol, known as the Mean King problem. The protocol uses a two way quantum channel. We show security against coherent attacks in a transmission-error free scenario, even if Eve is allowed to attack both transmissions. This establishes a connection between retrodiction and key distribution.

Quantum discord as a resource for quantum cryptography

Quantum discord is the minimal bipartite resource which is needed for a secure quantum key distribution, being a cryptographic primitive equivalent to non-orthogonality. Its role becomes crucial in device-dependent quantum cryptography, where the presence of preparation and detection noise (inaccessible to all parties) may be so strong to prevent the distribution and distillation of entanglemen...

From retrodiction to Bayesian quantum imaging

We employ quantum retrodiction to develop a robust Bayesian algorithm for reconstructing the intensity values of an image from sparse photocount data, while also accounting for detector noise in the form of dark counts. This method yields not only a reconstructed image but also provides the full probability distribution function for the intensity at each pixel. We use simulated as well as real ...

Comment on “ Time asymmetry in quantum mechanics: a retrodiction paradox”

It is shown that the “retrodiction paradox” recently introduced by Peres [Phys. Lett. A 194 ( 1994) 211 arises not because of the fallacy of the time-symmetric approach as he claimed, but due to an inappropriate use of retrodiction. In a recent Letter [ 11 Peres claimed that our timesymmetric approach to quantum theory [2,3], in which retrodictions and predictions are on an equal footing, leads...

Quantum Cryptography