Public Quantum Communication

Jonathan Oppenheim (University of Cambridge)

 

Is there a meaningful quantum counterpart to public communication? We argue that the symmetric-side channel — which distributes quantum information symmetrically between the receiver and the environment — is a good candidate for a notion of public quantum communication in entanglement distillation and quantum error correction. This connection is partially motivated by the quantum one time pad in the presence of an eavesdropper [Brandão and Oppenheim, arXiv:1004.3328]. This is a fully quantum cryptographic problem — a shared quantum state allows two parties to send private messages or private quantum states over a public quantum channel. If the eavesdropper intercepts the public quantum communication she learns nothing about the message. In the classical case, a one-time pad can be created using shared and partially private correlations. In the quantum case using public quantum communication, one finds the single letter formula for the rate at which the two parties can send messages using a quantum one-time pad.