We report on two experiments implementing quantum communications primitives in linear optics systems: a secure Quantum Random Bit Generator (QRBG) and a multi-qubit gate based on Two-Photon Multiple-Qubit (TPMQ) quantum logic. In the first we use photons to generate random numbers and introduce and implement a physics-based estimation of the sequence randomness as opposed to the commonly used statistical tests. This scheme allows one to detect and neutralize attempts to eavesdrop or influence the random number sequence. We also demonstrate a C-SWAP gate that can be used to implement quantum signature and fingerprinting protocols. A source of momentum-entangled photons, remote state preparation, and a C-SWAP gate are the ingredients used for this proof-of-principle experiment. While this implementation cannot be used in field applications due to the limitations of TPMQ logic, it provides useful insights into this protocol.

Date Published: 29 August 2006
PDF: 10 pages
Proc. SPIE 6305, Quantum Communications and Quantum Imaging IV, 63050E (29 August 2006); doi: 10.1117/12.681628

Published in SPIE Proceedings Vol. 6305:
Quantum Communications and Quantum Imaging IV
Ronald E. Meyers; Yanhua Shih; Keith S. Deacon, Editor(s)