Entanglement production by quantum error correction in the presence of correlated environmentG. De Chiara1, R. Fazio1, C. Macchiavello2 and G. M. Palma3
1 NEST-INFM and Scuola Normale Superiore - piazza dei Cavalieri 7 I-56126 Pisa, Italy
2 INFM and Dipartimento di Fisica "A. Volta", Università degli Studi di Pavia Via Bassi 6, I-27100 Pavia, Italy
3 NEST-INFM and Dipartimento di Tecnologie dell'Informazione Università degli Studi di Milano - via Bramante 65, I-26013 Crema (CR), Italy
(Received 7 May 2004; accepted in final form 18 June 2004)
We analyze the effect of a quantum error correcting code on the entanglement of encoded logical qubits in the presence of a dephasing interaction with a correlated environment. Such correlated reservoir introduces entanglement between physical qubits. We show that for short times the quantum error correction interprets such entanglement as errors and suppresses it. However, for longer time, although quantum error correction is no longer able to correct errors, it enhances the rate of entanglement production due to the interaction with the environment.
03.67.Pp - Quantum error correction and other methods for protection against decoherence.
03.67.Mn - Entanglement production, characterization and manipulation.
03.65.Yz - Decoherence; open systems; quantum statistical methods.
© EDP Sciences 2004