Subject C : Multi-bit entanglement control and optical interface with Superconducting circuits

Superconducting circuit-QED and quantum transducer

The University of Tokyo (Yasunobu Nakamura)
Nippon Telegraph and Telephone Corporation
Tokyo Medical and Dental University
Tohoku University

There are many candidates for the system to realize quantum information processing, and each system has its own advantage and disadvantage. So a hybrid approach to take the best of several systems is appealing for practical quantum information processing. One of promising hybrid approaches is to combine an optical photon, an atomic ensemble, and a superconducting qubit. A photon is almost decoherence free and so this can mediate an interaction between distant systems. An atomic ensemble has a strong coupling both with an optical photon and with a superconducting qubit, and therefore the atomic ensemble can transfer the information from the optical photon to the superconducting qubit. A superconducting qubit offers us an excellent controllability of quantum states involved in the processing. A combined system of these three would be utilized for robust implementation of quantum repeaters and distributed quantum computation.

Explore elementary technologies towards realization of quantum repeater nodes using superconducting circuits for entanglement swapping