Showing papers by "Rainer Blatt published in 1991"

A 12-GHz Standard Clock on Trapped Ytterbium Ions†

Abstract: The ground-state hyperfine transition ΔmF = 0 of trapped Yb+ ions has been measured as 12642812119.6 (0.4) Hz. The frequency instability of a microwave, controlled by this resonance, is characterised by the standard deviation 2·10−11· (τ/sec)−1/2, where τ is the time separation of probes. The performance of this frequency standard or “clock” exceeds the stability of commercial cesium clocks and still offers major potential for improvement. Ein 12-GHz-Frequenznormal auf der Grundlage gespeicherter Ytterbium-Ionen Der Hyperfein-Ubergang ΔmF = 0 im Grundzustand gespeicherter Yb+-Ionen wurde zu 12642812119,6 (0,4) Hz gemessen. Die Instabilitat der Frequenz einer Mikrowelle, die durch diese Resonanz geregelt ist, wird durch die Standardabweichung 2·10−11 (τ/sec)−1/2 gekennzeichnet; τ ist der Zeitabstand der Proben. Dieses Frequenznormal — eine „Uhr” — ubertrifft die Stabilitat handelsublicher Caesium-Uhren und bietet noch erhebliche Moglichkeiten fur Verbesserungen.

Self-induced zeeman coherences in a Paul trap

Abstract: A new method for the measurement of motional frequencies and amplitudes of stored ions in a radio-frequency trap is presented. Ions oscillating in the trap potential and additionally subjected to a small magnetic field, undergo sublevel transitions between adjacent Zeeman states when their motional frequency is identical with the Larmor frequency in the applied magnetic field. These transitions can be sensitively detected by means of an optical pumping scheme. As they are related to a coherent superposition of adjacent states and originate from the inherent motion of the ions in a slightly inhomogeneous magnetic field, this phenomenon is termed self-induced Zeeman coherence.