Single photons, Entangled photons, and Quantum Info-Communication

Ikuo Suemune, H. Kumano, Hirotaka Sasakura

Miwa Sasaki

We review our experiment on quantum source and channel codings, the most fundamental operations in quantum info-communications. For both codings, entangling letter states is essential. Our model is based on the polarization-location coding, and a quasi-single photon linear optics implementation to entangle the polarization and location degrees of freedom. Using single-photon events in a subset of possible cases, we simulate quantum coding-decoding operations for nonorthogonal states under the quasi-pure state condition. In the quantum channel coding, we double the spatial bandwidth (number of optical paths), and demonstrate the information more than double can be transmitted. In the quantum source coding, we halve the spatial bandwidth to compress the data and decompress the original data with the high fidelity approaching the theoretical limit.

Zhen-Sheng Yuan, Xiao‐Hui Bao, Chao‐Yang Lu +3 more

Anton Zeilinger

T. Yamaguchi, Ryōsuke Shimizu, Yasuyoshi Mitsumori +2 more

Polarization entanglement of photons provides a superior environment to demonstrate quantum info-communication protocols. Thus far, several methods using parametric down-conversion process have been realized to generate polarization-entangled photon pairs. In this report, we propose a novel method to generate polarization entanglement from spatially correlated photon pairs and demonstrate its experimental verification.

Harald Weinfurter