Quantum Communication in Rindler Spacetime

A state that an inertial observer in Minkowski space perceives to be the vacuum will appear to an accelerating observer to be a thermal bath of radiation. We study the impact of this Davies-Fulling-Unruh noise on communication, particularly quantum communication from an inertial sender to an accelerating observer and private communication between two inertial observers in the presence of an accelerating eavesdropper. In both cases, we establish compact, tractable formulas for the associated communication capacities assuming encodings that allow a single excitation in one of a fixed number of modes per use of the communications channel. Our contributions include a rigorous presentation of the general theory of the private quantum capacity as well as a detailed analysis of the structure of these channels, including their group-theoretic properties and a proof that they are conjugate degradable. Connections between the Unruh channel and optical amplifiers are also discussed.Comment: v3: 44 pages, accepted in Communications in Mathematical Physic

Can coastal fisheries bear the cost of sea turtle conservation: evidence from the east coast of peninsular Malaysia

[Extract] The threats of incidental catch of sea turtles are widely recognized and are becoming a major issue in fisheries management with increasing studies that record the impacts of fishing operations on sea turtles (Frazier and Montero 1990; Aguilar et al. 1995; Ovaretz 1999; Peckham et al. 2007; Alfaro-Shigueto and Mangel, chapter 15 [this volume]; Yeo et al., chapter 16 [this volume]). Recognition is growing of the need to minimize the ..