Potential energy curves for the interaction of Ag(5s) and Ag(5p) with noble gas atoms

We investigate the interaction of ground and excited states of a silver atom with noble gases (NG), including helium. Born-Oppenheimer potential energy curves are calculated with quantum chemistry methods and spin-orbit effects in the excited states are included by assuming a spin-orbit splitting independent of the internuclear distance. We compare our results with experimentally available spectroscopic data, as well as with previous calculations. Because of strong spin-orbit interactions, excited Ag-NG potential energy curves cannot be fitted to Morse-like potentials. We find that the labeling of the observed vibrational levels has to be shifted by one unit

A fundamental limit to the efficiency of spin-exchange optical pumping of 3He nuclei

We establish the existence of a fundamental limit to the efficiency of spin-exchange optical pumping of 3He nuclei by collisions with spin-polarized alkali-metal atoms. Using accurate ab initio calculations of molecular interactions and scattering properties, we show that the maximum 3He spin polarization that can be achieved in spin-exchange collisions with potassium (39K) and silver (107Ag) atoms is limited by the anisotropic hyperfine interaction. We find that spin exchange in Ag-He collisions occurs much faster than in K-He collisions, suggesting the possibility of using Ag in spin-exchange optical pumping experiments to increase the production rate of hyperpolarized 3He. Our analysis indicates that measurements of trap loss rates of 2S atoms in the presence of cold 3He gas may be used to probe anisotropic spin-exchange interactions in atom-He collisions.Comment: 5 pages, 4 figure

Lyotropic Liquid Crystalline Phases for the Formulation of Future Functional Foods

The especial features and advanced characteristics of Lyotropic Liquid Crystalline (LLC) phases as potent nano materials for encapsulation and the development of novel delivery systems for nutraceuticals and other bioactive compounds are reviewed. Exemplary, a focus is set on the health benefits of flavonoids and their current restrictions in bioavailability. Accordingly, our visions for application of LLC phases in the engineering of enhanced flavonoid-based food supplements and correlated challenges to over come are highlighted

Influence of monolayer contamination on electric-field-noise heating in ion traps

Electric field noise is a hinderance to the assembly of large scale quantum computers based on entangled trapped ions. Apart from ubiquitous technical noise sources, experimental studies of trapped ion heating have revealed additional limiting contributions to this noise, originating from atomic processes on the electrode surfaces. In a recent work [A. Safavi-Naini et al., Phys. Rev. A 84, 023412 (2011)] we described a microscopic model for this excess electric field noise, which points a way towards a more systematic understanding of surface adsorbates as progenitors of electric field jitter noise. Here, we address the impact of surface monolayer contamination on adsorbate induced noise processes. By using exact numerical calculations for H and N atomic monolayers on an Au(111) surface representing opposite extremes of physisorption and chemisorption, we show that an additional monolayer can significantly affect the noise power spectrum and either enhance or suppress the resulting heating rates.Comment: 8 pages, 5 figure

Groundwater Lowering in Deep Excavation (Case Study: Foundation Excavation of Shahid Madani Dam)

In many big civil constructions, deep excavation is an essential part of project and groundwater control in excavation process is the prominent tasks. In this paper while mentioning the risks of deep excavation, the solutions of underground water control have been explained and different methods of groundwater control in regard to financial conditions, different soil condition and various depths have been investigated. Groundwater control in foundation excavation of Shahid Madani Dam as a case study is presented. Depth of foundation excavation was about 50 meters in tight valley and excavation was performed under groundwater table. This excavation is one of the deepest excavations in Iran and it has some specific problems related to topographical and geotechnical condition in dam site. Finally the proper methods for groundwater control are presented and recommended. Measurements in excavation period and in the middle of dam body construction have shown that this design method had a good performance

Study of Instability Event of Rock Trench in Vanyar Dam Spillway

Vanyar dam is located near Tabriz city, North West of Iran. The side channel overflow spillway of this dam is located on the left side of dam body with discharge capacity of 1330 m3/sec. To construct this spillway a soil-rock slope with height of maximum 140m is excavated. After about three years, some surface cracks and slides started to develop. This research tries to study the reasons of these instabilities and some approaches are presented to stabilize the slope. This slope is located on too weathered and crushed igneous rocks and weak sandstones. The field studies indicated that the most important reasons of these instability events were rainfall penetration, weathering, freezing and melting cycles, static and dynamic loading conditions, increase in slope height, tectonic conditions and shotcrete covering. To stabilize the slope meanwhile doing back analysis, many methods evaluated and considering to advantages and disadvantages of each method and available equipment, some approaches such as: adjustment of the slope gradients, improvement of drainage system, construction of retaining structure, vegetation and stabilizing instable parts of rocks are recommended as remedy works in this case

Tuning p-wave interactions in an ultracold Fermi gas of atoms

We have measured a p-wave Feshbach resonance in a single-component, ultracold Fermi gas of potassium atoms. We have used this resonance to enhance the normally suppressed p-wave collision cross-section to values larger than the background s-wave cross-section between potassium atoms in different spin-states. In addition to the modification of two-body elastic processes, the resonance dramatically enhances three-body inelastic collisional loss.Comment: 4 pages, 5 figure

Electric-field noise from carbon-adatom diffusion on a Au(110) surface: first-principles calculations and experiments

The decoherence of trapped-ion quantum gates due to heating of their motional modes is a fundamental science and engineering problem. This heating is attributed to electric-field noise arising from the trap-electrode surfaces. In this work, we investigate the source of this noise by focusing on the diffusion of carbon-containing adsorbates on the surface of Au(110). We show by density functional theory, based on detailed scanning probe microscopy, how the carbon adatom diffusion on the gold surface changes the energy landscape, and how the adatom dipole moment varies with the diffusive motion. A simple model for the diffusion noise, which varies quadratically with the variation of the dipole moment, qualitatively reproduces the measured noise spectrum, and the estimate of the noise spectral density is in accord with measured values.Comment: 8 pages, 6 figure