Scalable arrays of RF Paul traps in degenerate Si

We report techniques for the fabrication of multi-zone linear RF Paul traps that exploit the machinability and electrical conductivity of degenerate silicon. The approach was tested by trapping and laser cooling 24Mg+ ions in two trap geometries: a single-zone two-layer trap and a multi-zone surface-electrode trap. From the measured ion motional heating rate we determine an electric field spectral density at the ion's position of approximately 1E-10 (V/m)^2/Hz at a frequency of 1.125 MHz when the ion lies 40 micron above the trap surface. One application of these devices is controlled manipulation of atomic ion qubits, the basis of one form of quantum information processing.Comment: 3 pages; 2 figures; v2: fix heating rate typ

Selection for Greater β-Glucan Content in Oat Grain

Oat (Avena sativa L.) β-glucan lowers serum cholesterol in humans. Development of oat cultivars with greater groat (caryopsis) β-glucan content would increase the nutritional and economic value of the crop. The objectives of this experiment were to evaluate the response to phenotypic selection among individual S0 plants for greater groat β-glucan content in two genetically broad-based populations; to compare selected experimental lines to standard check cultivars; and to estimate genetic variances and heritabilities and to test for nonadditive genetic variance for β-glucan content. We measured groat β-glucan contents of check cultivars and parental lines and random S0:1 lines from initial and selected generations of each population grown in field experiments in 1996 and 1997 at two Iowa locations. Mean β-glucan content increased from 53.9 to 59.9 g kg−1 in one population, and from 63.5 to 66.0 g kg−1 in the other, following selection. Genetic variance of β-glucan content decreased by 9 to 22% following selection, but heritability for β-glucan content did not change significantly. Heritability estimates ranged from 0.80 to 0.85 on a line mean basis. Additive variance was the only substantial component of genetic variance. Some experimental lines had significantly greater β-glucan content than the best check cultivars and lines. Phenotypic selection for greater groat β-glucan content will be effective for developing cultivars with elevated β-glucan contents

Transport of charged particles by adjusting rf voltage amplitudes

We propose a planar architecture for scalable quantum information processing (QIP) that includes X-junctions through which particles can move without micromotion. This is achieved by adjusting radio frequency (rf) amplitudes to move an rf null along the legs of the junction. We provide a proof-of-principle by transporting dust particles in three dimensions via adjustable rf potentials in a 3D trap. For the proposed planar architecture, we use regularization techniques to obtain amplitude settings that guarantee smooth transport through the X-junction.Comment: 16 pages, 10 figure

Quantum control of 88^{88}Sr+^+ in a miniature linear Paul trap

We report on the construction and characterization of an apparatus for quantum information experiments using $^{88}$Sr$^+$ ions. A miniature linear radio-frequency (rf) Paul trap was designed and built. Trap frequencies above 1 MHz in all directions are obtained with 50 V on the trap end-caps and less than 1 W of rf power. We encode a quantum bit (qubit) in the two spin states of the $S_{1/2}$ electronic ground-state of the ion. We constructed all the necessary laser sources for laser cooling and full coherent manipulation of the ions' external and internal states. Oscillating magnetic fields are used for coherent spin rotations. High-fidelity readout as well as a coherence time of 2.5 ms are demonstrated. Following resolved sideband cooling the average axial vibrational quanta of a single trapped ion is $\bar n=0.05$ and a heating rate of $\dot{\bar n}=0.016$ ms$^{-1}$ is measured.Comment: 8 pages,9 figure

Fluorescence during Doppler cooling of a single trapped atom

We investigate the temporal dynamics of Doppler cooling of an initially hot single trapped atom in the weak binding regime using a semiclassical approach. We develop an analytical model for the simplest case of a single vibrational mode for a harmonic trap, and show how this model allows us to estimate the initial energy of the trapped particle by observing the fluorescence rate during the cooling process. The experimental implementation of this temperature measurement provides a way to measure atom heating rates by observing the temperature rise in the absence of cooling. This method is technically relatively simple compared to conventional sideband detection methods, and the two methods are in reasonable agreement. We also discuss the effects of RF micromotion, relevant for a trapped atomic ion, and the effect of coupling between the vibrational modes on the cooling dynamics.Comment: 12 pages, 11 figures, Submitted to Phys. Rev.

Scalable ion traps for quantum information processing

We report on the design, fabrication, and preliminary testing of a 150 zone array built in a `surface-electrode' geometry microfabricated on a single substrate. We demonstrate transport of atomic ions between legs of a `Y'-type junction and measure the in-situ heating rates for the ions. The trap design demonstrates use of a basic component design library that can be quickly assembled to form structures optimized for a particular experiment