Quantum computation with linear optics
Michael J. Fitch, Michelle M. Donegan, B. C. Jacobs, T. B. Pittman, J. D. Franson · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2003
Ever since Knill, Laflamme and Milburn [Nature (London) 409, 46 (2001)] showed that nondeterministic quantum logic operations could be performed with linear optical elements, additional photons (ancilla) and projective measurements, the idea of linear-optics quantum computation has attracted considerable interest. Our group has recently demonstrated several devices of this kind. We give an overview of recent experimental results, including the quantum parity check, the destructive controlled-NOT, and a cyclical quantum memory. The need for high-efficiency detection of single photons, and for detectors capable of distinguishing photon number will be discussed. Some experimental improvements towards meeting that need will be presented.