Search

We report a high-accuracy measurement of the differential static scalar polarizability Δα0 of the 5s2S1/2-4d2D5/2 transition of the 88Sr+ ion. The high accuracy is obtained by comparing the micromotion-induced positive scalar Stark shift to the negative time-dilation shift. Measurement of the trap drive frequency where these shifts cancel is used to determine Δα0 without the need to determine the electric field. Δα0 is a critical parameter for the operation of frequency standards as it determines the blackbody radiation frequency shift coefficient, the largest source of uncertainty in the 88Sr+ ion clock. The measured value of Δα0 is -4.7938(71) × 10-40 J m2/V2. Taking into account the dynamic correction, the blackbody shift at 300 K is 0.247 99(37) Hz. The contribution of the blackbody shift coefficient to the uncertainty of the ion standard has been reduced by a factor of 24, from 2 × 10-17 to 8.3 ×10-19. The revised total uncertainty of our reference standard is 1.2 × 10-17, limited by the blackbody field evaluation. An additional benefit of the low uncertainty of Δα0 is the ability to suppress, by a factor of about 200, the net micromotion frequency shifts. [ABSTRACT FROM AUTHOR]

The article presents information on a study which focuses on the high-accuracy measurement of the differential static scalar polarizability of a 88Sr(strontium)+ atomic Clock. It compares the micromotion-induced positive scalar Stark shift to the negative time-dilation shift, and measures trap drive frequency, without the need of determining the electric field.

Proper time, ideal clocks, and boosts are well understood classically, but subtleties arise in quantum physics. We show that quantum clocks set in motion via momentum boosts do not witness classical time dilation. However, using velocity boosts we find the ideal behavior in both cases, where the quantum clock and classical observer are set in motion. Without internal state-dependent forces additional effects arise. As such, we derive observed frequency shifts in ion trap atomic clocks, indicating a small additional shift, and also show the emergence of nonideal behavior in a theoretical clock model. [ABSTRACT FROM AUTHOR]