Search for correlation effects in linear chains of trapped ions

¹ Centre for Quantum Computation, Department of Atomic and Laser Physics University of Oxford, Clarendon Laboratory - Parks Road, Oxford OX1 3PU, UK
² Institut für Experimentalphysik, Universität Innsbruck Technikerstr. 25, A-6020 Innsbruck, Austria
³ L'Institut d'Optique, Université de Paris Sud - Orsay, France

Received: 7 April 2000
Accepted: 27 June 2000

Abstract

We report a precise search for correlation effects in linear chains of 2 and 3 trapped Ca⁺ ions. Unexplained correlations in photon emission times within a linear chain of trapped ions have been reported, which, if genuine, cast doubt on the potential of an ion trap to realize quantum information processing. We observe quantum jumps from the metastable level for several hours, searching for correlations between the decay times of the different ions. We find no evidence for correlations: the number of quantum jumps with separations of less than 10 ms is consistent with statistics to within errors of ; the lifetime of the metastable level derived from the data is consistent with that derived from independent single-ion data at the level of the experimental errors (); and no rank correlations between the decay times were found with sensitivity to rank correlation coefficients at the level of |R| = 0.024.