Sources

Rudolf Haag

Christopher King, Andrezj Leśniewski

We define a large class of quantum sources and prove a quantum analog of the asymptotic equipartition property. Our proof relies on using local measurements on the quantum source to obtain an associated classical source. The classical source provides an upper bound for the dimension of the relevant subspace of the quantum source, via the Shannon–McMillan noiseless coding theorem. Along the way we derive a bound for the von Neumann entropy of the quantum source in terms of the Shannon entropy of the classical source, and we provide a definition of ergodicity of the quantum source. Several explicit models of quantum sources are also presented.

Philipp Niemann, Robert Wille

Reevana Balmahoon, A. J. Han Vinck, Ling Cheng

Correlated sources are present in communication systems where protocols ensure that there is some predetermined information for sources. Here, we investigate two correlated sources across the wiretap channel II and their effect on the information leakage when some channel information and some source data symbols (the predetermined information) have been wiretapped. The adversary in this situation has access to more information than if a link is wiretapped only and can thus determine more about a particular source. We show that since the sources are correlated, if the information on one link and a portion of its data symbols are compromised then there is also information leakage for the other source. Further, we describe a method to reduce the information leakage for the scenario where the information from the source data symbols overlaps with the channel information.

Christopher King, Lesniewski, A

Abstract. We define a large class of quantum sources and prove a quantum analog of the asymptotic equipartition property. Our proof relies on using local measurements on the quantum source to obtain an associated classical source. The classical source provides an upper bound for the dimension of the relevant subspace of the quantum source, via the Shannon-McMillan noiseless coding theorem. Along the way we derive a bound for the von Neumann entropy of the quantum source in terms of the Shannon entropy of the classical source, and we provide a definition of ergodicity of the quantum source. Several explicit models of quantum sources are also presented. 1 Supported in part by the National Science Foundation under grant DMS-9424344C. KING and A. LESNIEWSKI

Niklas Büscher, Stefan Katzenbeisser