Active suppression of dephasing in Josephson-junction qubits
D. V. Averin, R. Fazio+
Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794-3800
+NEST-INFM & Scuola Normale Superiore, 56126 Pisa, Italy
PACS: 03.67.Pp, 85.25.Cp
Abstract
Simple majority code correcting k dephasing errors by encoding
a qubit of information into 2k+1 physical qubits is studied
quantitatively. We derive an equation for quasicontinuous evolution
of the density matrix of encoded quantum information under the
error correction procedure in the presence of correlated dephasing noise.
A specific design of a Josephson-junction nanocircuit implementing
this scheme is suggested.