Quantum Computation and Information Seminar 

24/04/2009, 15:00 — 16:00 — Room P4.35, Mathematics Building
Vittorio Giovannetti, Scuola Normale Superiore, Pisa

Capacities of Lossy Bosonic Memory Channels

We introduce a general model for a lossy bosonic memory channel and calculate the classical and the quantum capacity, proving that coherent state encoding is optimal. The use of a proper set of collective field variables allows to unravel the memory, showing that the n-fold concatenation of the memory channel is unitarily equivalent to the direct product of n single-mode lossy bosonic channels.