No Arabic abstract
A generalized probe sequence typical of trapped ion experiments using shelving is studied. Detection efficiency is analyzed for finite shelved state lifetimes and using multi-modal count distributions. Multi-modal distributions are more appropriate for measurements that use a small number of ions than the simple Poisson counting statistics usually considered and have a larger variance that may be significant in determining uncertainties and in making weighted fits. Optimal probe times and the resulting state detection efficiency and sensitivity are determined for arbitrary cooling rates, initial states and shelved state lifetimes, in terms of a probe coherence time {tau}p. A universal optimal probe time of tp ~ 0.43{tau}p is shown to give an almost optimal probe sensitivity for most systems.
We introduce a measurement scheme that utilizes a single ion as a local field probe. The ion is confined in a segmented Paul trap and shuttled around to reach different probing sites. By the use of a single atom probe, it becomes possible characterizing fields with spatial resolution of a few nm within an extensive region of millimeters. We demonstrate the scheme by accurately investigating the electric fields providing the confinement for the ion. For this we present all theoretical and practical methods necessary to generate these potentials. We find sub-percent agreement between measured and calculated electric field values.
We have employed the 12.6 GHz microwave transition resonance of a single trapped$^{171}$Yb+ ion to accurately measure the size and relative orientation of the magnetic and optical electric fields at the position of the ion in the trap. Accurate knowledge of these fields is required for precision experiments such as single ion PNC. As a proof of the principle we have measured the polarization dependent light-shift of the ground state hyperfine levels due to the 369 nm cooling laser to determine its electric field amplitude and polarization.
Measuring and understanding electric field noise from bulk material and surfaces is important for many areas of physics. In this work, we introduce a method to detect in situ different sources of electric field noise using a single trapped ion as a sensor. We demonstrate the probing of electric field noise as small as $S_E = 5.2(11)times 10^{-16},text{V}^2text{m}^{-2}text{Hz}^{-1}$, the lowest noise level observed with a trapped ion to our knowledge. Our setup incorporates a controllable noise source utilizing a high-temperature superconductor. This element allows us, first, to benchmark and validate the sensitivity of our probe. Second, to probe non-invasively bulk properties of the superconductor, observing for the first time a superconducting transition with an ion. For temperatures below the transition, we use our setup to assess different surface noise processes. The measured noise shows a crossover regime in the frequency domain, which cannot be explained by existing surface noise models. Our results open perspectives for new models in surface science and pave the way to test them experimentally.
Atomic Parity Violation provides the rare opportunity of a low energy window into possible new fundamental processes at very high mass scales normally investigated at large high energy accelerators. Precise measurements on atomic systems are currently the most sensitive probes of many kinds of new physics, and complement high energy experiments. Present atomic experiments are beginning to reach their limits of precision due to either sensitivity, systematics or atomic structure uncertainties. An experiment in a single trapped Barium ion can improve on all of these difficulties. This experiment uses methods to precisely manipulate and detect the spin state of a single ion in order to measure a parity induced splitting of the ground state magnetic sublevels in externally applied laser fields. The same methods can be used to provide precise measurements of more conventional atomic structure parameters.
We present a spectroscopy scheme for the 7-kHz-wide 689-nm intercombination line of strontium. We rely on shelving detection, where electrons are first excited to a metastable state by the spectroscopy laser before their state is probed using the broad transition at 461 nm. As in the similar setting of calcium beam clocks, this enhances dramatically the signal strength as compared to direct saturated fluorescence or absorption spectroscopy of the narrow line. We implement shelving spectroscopy both in directed atomic beams and hot vapor cells with isotropic atomic velocities. We measure a fractional frequency instability $sim 2 times 10^{-12}$ at 1 s limited by technical noise - about one order of magnitude above shot noise limitations for our experimental parameters. Our work illustrates the robustness and flexibility of a scheme that can be very easily implemented in the reference cells or ovens of most existing strontium experiments, and may find applications for low-complexity clocks.