We propose an architecture and methodology for large-scale quantum simulations using hyperfine states of trapped ions in an arbitrary-layout microtrap array with laserless interactions. An ion is trapped at each site, and the electrode structure provides for the application of single and pairwise evolution operators using only locally created microwave and radio-frequency fields. The avoidance of short-lived atomic levels during evolution effectively eliminates errors due to spontaneous scattering; this may allow scaling of quantum simulators based on trapped ions to much larger systems than currently estimated. Such a configuration may also be particularly appropriate for one-way quantum computing with trapped-ion cluster states.

An experimental investigation of nonlinear interactions between shear Alfvén waves in a laboratory plasma is presented. Two Alfvén waves, generated by a resonant cavity, are observed to beat together, driving a pseudomode at the beat frequency. The pseudomode then scatters the Alfvén waves, generating a series of sidebands. The observed interaction is very strong, with the normalized amplitude of the driven pseudomode comparable to the normalized magnetic field amplitude (deltaB/B) of the interacting Alfvén waves.

We present a high-precision measurement of the isotope shift of the narrow quadrupole-allowed 5 2 S 1/2 -4 2 D 5/2 transition in 86 Sr + relative to the most abundant isotope 88 Sr + . This was accomplished using high-resolution laser spectroscopy of individual trapped ions, and the measured shift is ν 88,86 meas = 570.281(4) MHz. We also tested a recently developed and successful method for ab initio calculation of isotope shifts in alkali-metal-like atomic systems against this measurement, and our initial result of ν 88,86 calc = 457 (28) MHz is also presented. While the measurement and the calculation are in broad agreement, there is a clear discrepancy between them, and we believe that the specific mass shift was underestimated in our calculation. Our measurement provides a stringent test for further refinements of theoretical isotope shift calculation methods for atomic systems with a single valence electron.

The optically pumped, vapor-cell atomic clock is a work horse of precise timekeeping, finding applications onboard global navigation satellites as well as at cellular communications base stations. At the heart of the device is the relatively simple alkali rf-discharge lamp, which enables the production of the atomic-clock signal and the sensing of the atoms' response to resonant microwaves. In the lamp, electrons extract energy from an rf-field via elastic collisions with noble-gas buffer atoms; the energetic electrons then ionize Rb atoms; finally, resonant light for optical pumping is produced through Rb + /electron recombination at the lamp's glass walls. Unfortunately, recent research has shown that alkali rf-discharge lamps slowly lose their buffer gas, giving rise to a life-limiting mechanism for the rf-discharge lamp and hence the atomic clock. Here, we review the literature on buffer-gas loss in alkali rf-discharge lamps and discuss a likely mechanism for the process. We then discuss the dependence of the discharge's electron temperature on rf-frequency, and how this might be used as a critical test of the proposed mechanism.Index Terms-Alkali discharge lamp, atomic clocks, inductively-coupled plasma, noble-gas ionization, Rb atomic clock.