Beating the channel capacity limit for superdense coding with entangled ququarts.

The article offers information on a study regarding beating the channel capacity limit for superdense coding (SDC) with entangled ququarts. It mentions that the SDC with high-dimensional entanglement is promising in the future. It states that the photon pairs are generated from ppKTP, the overall detection efficiency can be as high when using careful alignment and superconductor detectors.