Single-channel theory for the determination of radiation lifetimes

H. Shao, H. Yue, Zhiyao Ma +3 more

We present a method to precisely determine the $^{2}D_{3/2}$ state lifetime of a single trapped $^{174}\mathrm{Yb}^{+}$ ion. This method is based on the detection of photons emitted from excited states, where a highly synchronized measurement sequence for laser control and an intensity-alternating sequence for atomic excitation and photon counting are used to minimize systematic errors. This method is easy to implement and is immune to fluctuations of magnetic field, laser intensity, and frequency detuning. Combined with the real-time approach of background photon correction, the radiative lifetime of the $^{2}D_{3/2}$ state is determined to be $54.83\ifmmode\pm\else\textpm\fi{}0.18$ ms, which represents an order of magnitude improvement in measurement precision. The accurately determined lifetime sets a benchmark for many-body atomic theories and is particularly useful to determine the coherence time limit of the optical clock.

Stephen J. Gustafson, Israel Michael Sigal

Masami Yasuda, Hidetoshi Katori

We have measured the lifetime of the 5s5p 3P2 metastable state of strontium atoms by magneto-optically trapping the decayed atoms to the ground state, which allowed sensitive detection of the rare decay events. We found that the blackbody radiation-induced decay was the dominant decay channel for the state at T=300 K. The lifetime was determined to be 520(+310)(-140) s in the limit of zero temperature, arguably the longest lifetime ever determined in a laboratory environment.

Stephen J. Gustafson, Israel Michael Sigal

Ziv Meir, Mudit Sinhal, Marianna S. Safronova +1 more

We report a precise determination of the lifetime of the $(4p){\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}$ state of $^{40}\mathrm{Ca}^{+}$, ${\ensuremath{\tau}}_{{P}_{3/2}}=6.639(42)\phantom{\rule{0.16em}{0ex}}\mathrm{ns}$, using a combination of measurements of the induced light shift and scattering rate on a single trapped ion. Good agreement with the result of a recent high-level theoretical calculation, 6.69(6) ns [M. S. Safronova et al., Phys. Rev. A 83, 012503 (2011)], but a 6-$\ensuremath{\sigma}$ discrepancy with the most precise previous experimental value, 6.924(19) ns [J. Jin et al., Phys. Rev. Lett. 70, 3213 (1993)], is found. To corroborate the consistency and accuracy of the new measurements, relativistically corrected ratios of reduced-dipole-matrix elements are used to directly compare our result with a recent result for the ${P}_{1/2}$ state, yielding a good agreement. The application of the present method to precise determinations of radiative quantities of molecular systems is discussed.

Siegfried Flügge