Measurement of the lifetime of the 3d2D5/2 state in 40Ca+
Physical Review A - Atomic, Molecular, and Optical Physics 62:3 (2000) 032503-032501
Abstract:
A linear ion trap apparatus was used to measure the lifetime of the D5/2 level in 40Ca+ by quantum jump measurements on a single trapped ion. Compared to previous measurements, more precise and significantly larger results were obtained. Overall, the apparatus provided a precise test of ab initio atomic structure calculations.Search for correlation effects in linear chains of trapped Ca+ ions
Europhysics Letters 51:4 (2000) 388-394
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 met astable 3d2 D5/2 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 0.05%; 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 (1%); and no rank correlations between the decay times were found with sensitivity to rank correlation coefficients at the level of |R| = 0.024.Measurement of the 1s − 2s energy interval in muonium
Physical Review Letters 84:6 (2000) 1136-1139
Abstract:
The 1s − 2s interval has been measured in the muonium(μ+e− atom by Doppler-free two-photon pulsed laser spectroscopy. The frequency separation of the states was determined to be 2 455 528 941.0(9.8) MHz, in good agreement with quantum electrodynamics. The result may be interpreted as a measurement of the muon-electron charge ratio as −1−1.1(2.1) × 10−9. We expect significantly higher accuracy at future high flux muon sources and from cw laser technology. © 2000 American Physical Society.Quantum computing with trapped ions, atoms and light
Fortschritte der Physik 48:9-11 (2000) 839-858
Abstract:
We first consider the basic requirements for a quantum computer, arguing for the attractiveness of nuclear spins as information-bearing entities, and light for the coupling which allows quantum gates. We then survey the strengths of and immediate prospects for quantum information processing in ion traps. We discuss decoherence and gate rates in ion traps, comparing methods based on the vibrational motion with a method based on exchange of photons in cavity QED. We then sketch the main features of a quantum computer designed to allow an algorithm needing 106 Toffoli gates on 100 logical qubits. We find that around 200 ion traps linked by optical fibres and high-finesse cavities could perform such an algorithm in a week to a month, using components at or near current levels of technology.Measurement of the lifetime of the 3d 2D5/2 state in 40Ca+ -: art. no. 032503
PHYSICAL REVIEW A 62:3 (2000) ARTN 032503