Entanglement Transformation At Dielectric Four-Port Devices
Stefan Scheel, L. Knöll, Tomáš Opatrný, D.‐G. Welsch · Kluwer Academic Publishers eBooks · 2006
Quantum communication schemes widely use dielectric four-port devices as basic elements for constructing optical quantum channels. Dielectrics with complex permittivity are typical examples of noisy quantum channels in which quantum coherence will not be preserved. Basing on quantization of phenomenological electrodynamics, we construct the transformation relating the output quantum state to the input quantum state without placing frequency restrictions. Knowledge of the full transformed quantum state enables us to compute the entanglement contained in the output state.