Constructing finite-dimensional codes with optical continuous variablesS. Pirandola, S. Mancini, D. Vitali and P. Tombesi
INFM, Dipartimento di Fisica, Università di Camerino - I-62032 Camerino, Italy
received 27 February 2004; accepted in final form 31 August 2004
published online 1 October 2004
We show how a qubit can be fault-tolerantly encoded in the infinite-dimensional Hilbert space of an optical mode. The scheme is efficient and realizable with present technologies. In fact, it involves two travelling optical modes coupled by a cross-Kerr interaction, initially prepared in coherent states, one of which is much more intense than the other. At the exit of the Kerr medium, the weak mode is subject to a homodyne measurement and a quantum codeword is conditionally generated in the quantum fluctuations of the intense mode.
03.67.Pp - Quantum error correction and other methods for protection against decoherence.
42.65.-k - Nonlinear optics.
42.50.Gy - Effects of atomic coherence on propagation, absorption, and amplification of light; electromagnetically induced transparency and absorption.
© EDP Sciences 2004