Development of a quantum circuit dragging out the maximum information volume from a single photon state is a success!

Multivalued polarized wave modulation signals due to a single photon are the simplest signal systems when performing a principal demonstration of quantum signal detection theory. On the other hand, because limited errors must be accompanied by discriminating signals, using this reversibly also enables us to constitute protocols of quantum channel coding. In spite of being predicted of the presence so far against such signal systems, we succeeded in proving a group quantum optimal detection strategy that had not previously been experimentally proven. The strategy outputs up to ternary, and this facilitates extraction of the maximum information volume no matter what the value modulation signal numbers are. This signal detection circuit consists of simple polarization Mach-Zehnder interference systems and proved detection performance approximating 96% of the quantum optimal detection limit in prediction.

• Quantum communication