Quantum Logic Using Linear Optics

John G. Rarity

Chris Sparrow, Jacques Carolan, Christopher Harrold +13 more

J. D. Franson, Michelle M. Donegan, Michael J. Fitch +2 more

Knill, Laflamme, and Milburn [Nature (London) 409, 46 ((2001))]] have shown that quantum logic operations can be performed using linear optical elements and additional ancilla photons. Their approach is probabilistic in the sense that the logic devices fail to produce an output with a failure rate that scales as 1/n, where n is the number of ancilla. Here we present an alternative approach in which the logic devices always produce an output with an intrinsic error rate that scales as 1/n(2), which may have several advantages in quantum computing applications.

J. D. Franson, Michael J. Fitch, B. C. Jacobs +1 more

Quantum logic operations can be performed using linear optical elements, additional photons (ancilla), and feed-forward control based on the results of measurements on the ancilla. An experimental demonstration of several logic devices of this kind will be described, including a controlled-NOT logic gate for single photons.

Nobuyuki Matsuda

Christoph Adami, Nicolas J. Cerf