Long-Lived Qubit Memory Using Atomic Ions

C. Langer, R. Ozeri, J. D. Jost, J. Chiaverini, B. DeMarco, A. Ben-Kish, R. B. Blakestad, J. Britton, D. B. Hume, W. M. Itano, D. Leibfried, R. Reichle, T. Rosenband, T. Schaetz, P. O. Schmidt, and D. J. Wineland

Phys. Rev. Lett. 95, 060502 – Published 2 August 2005

Abstract

We demonstrate experimentally a robust quantum memory using a magnetic-field-independent hyperfine transition in atomic ion qubits at a magnetic field . We observe that the single physical qubit memory coherence time is greater than 10 s, an improvement of approximately 5 orders of magnitude from previous experiments with . We also observe long coherence times of decoherence-free subspace logical qubits comprising two entangled physical qubits and discuss the merits of each type of qubit.