Europhys. Lett.
Volume 68, Number 3, November 2004
Page(s) 323 - 329
Section General
Published online 01 October 2004
Europhys. Lett., 68 (3), pp. 323-329 (2004)
DOI: 10.1209/epl/i2004-10203-9

Constructing finite-dimensional codes with optical continuous variables

S. 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