9,526 research outputs found
Search For A Permanent Electric Dipole Moment Using Atomic Indium
We propose indium (In) as a possible candidate for observing the permanent
electric dipole moment (EDM) arising from the violations of parity (P) and
time-reversal (T) symmetries. This atom has been laser cooled and therefore the
measurement of its EDM has the potential of improving on the current best EDM
limit for a paramagnetic atom which comes from thallium. We report the results
of our calculations of the EDM enhancement factor due to the electron EDM and
the ratio of the atomic EDM to the electron-nucleus scalar-pseudoscalar (S-PS)
interaction coupling constant in In in the framework of the relativistic
coupled cluster theory. It might be possible to get new limits for the electron
EDM and the S-PS CP violating coupling constant by combining the results of our
calculations with the measured value of the EDM of In when it is available.
These limits could have important implications for the standard model (SM) of
particle physics.Comment: 5 pages, 1 fig, Rapid Communicatio
State-insensitive trapping of Rb atoms: linearly versus circularly polarized lights
We study the cancellation of differential ac Stark shifts in the 5s and 5p
states of rubidium atom using the linearly and circularly polarized lights by
calculating their dynamic polarizabilities. Matrix elements were calculated
using a relativistic coupled-cluster method at the single, double and important
valence triple excitations approximation including all possible non-linear
correlation terms. Some of the important matrix elements were further optimized
using the experimental results available for the lifetimes and static
polarizabilities of atomic states. "Magic wavelengths" are determined from the
differential Stark shifts and results for the linearly polarized light are
compared with the previously available results. Possible scope of facilitating
state-insensitive optical trapping schemes using the magic wavelengths for
circularly polarized light are discussed. Using the optimized matrix elements,
the lifetimes of the 4d and 6s states of this atom are ameliorated.Comment: 13 pages, 13 tables and 4 figure
Spectacular Role of Electron Correlation in the Hyperfine Interactions in States in Alkaline Earth Ions
The low-lying n(=3,4,5)d states alkaline earth ions are of vital
importance in a number of different physical applications. The hyperfine
structure constants of these states are characterized by unusually strong
electron correlation effects. Relativistic coupled-cluster theory has been
employed to carry out {\it ab initio} calculations of these constants. The role
of the all order core-polarization effects was found to be decisive in
obtaining good agreement of the results of our calculations with accurate
measurements. The present work is an apt demonstration of the power of the
coupled-cluster method to cope with strongly interacting configurations.Comment: Submitted to Physical Review Letters, 3 figures and 5 table
Spectroscopy on a single trapped 137Ba+ ion for nuclear magnetic octupole moment determination
We present precision measurements of the hyperfine intervals in the 5D3/2
manifold of a single trapped Barium ion, 137 Ba+ . Measurements of the
hyperfine intervals are made between mF = 0 sublevels over a range of magnetic
fields allowing us to interpolate to the zero field values with an accuracy
below a few Hz, an improvement on previous measurements by three orders of
magnitude. Our results, in conjunction with theoretical calculations, provide a
30-fold reduction in the uncertainty of the magnetic dipole (A) and electric
quadrupole (B) hyperfine constants. In addition, we obtain the magnetic
octupole constant (C) with an accuracy below 0.1 Hz. This gives a subsequent
determination of the nuclear magnetic octupole moment, {\Omega}, with an
uncertainty of 1% limited almost completely by the accuracy of theoretical
calculations. This constitutes the first observation of the octupole moment in
137 Ba+ and the most accurately determined octupole moment to date.Comment: 4 pages, 3 figure
Accurate estimations of circumstellar and interstellar lines of quadruply ionized vanadium using the coupled cluster approach
Accurate {\it ab initio} calculations have been carried out to study the
valence electron removal energies and oscillator strengths of astrophysically
important electromagnetic transitions of quadruply ionized vanadium, .
Many important electron correlations are considered to all-orders using the
relativistic coupled-cluster theory. Calculated ionization potentials and fine
structure splittings are compared with the experimental values, wherever
available. To our knowledge, oscillator strengths of electric dipole
transitions are predicted for the first time for most of the transitions. The
transitions span in the range of ultraviolet, visible and near infrared regions
and are important for astrophysical observations.Comment: Submitted in Astrophysical
Development and performance evaluation of manual/bullock operated multicrop planter for hilly region
In hills, sowing of various crops is generally performed manually by broadcasting of seeds, and that not only consume higher seed rate but also cause uneven distribution of seed at improper depth and moisture, poor germination, unhealthy plants and ultimately lower the yield. To overcome these problems, a single row manual/bullock multicrop planter was designed and developed for line sowing of wheat, maize, soybean, lentil, pea, mustard, millet etc. for hilly small fields. The power and pull requirements were 74.6 W and 12 kgf, respectively. The machine has a nylon made cell type seed metering mechanism with 4 types of cells of different sizes on a roller, and also has a fluted roller for fertilizer metering. Shovel type and Inverted T-type furrow openers can be used as the need. Two persons are required to operate the machine manually by one using handle and one with bullocks. The effective field capacity was observed 0.0378, 0.05, 0.058 and 0.056 hah-1 in wheat, lentil, mustard and pea, respectively. The cost of operation was observed 42% less in multicrop planter with 21%-33% increase in yield as compared to traditional broadcasting method
Generalized Brans-Dicke cosmology in the presence of matter and dark energy
We study the Generalized Brans-Dicke cosmology in the presence of matter and
dark energy. Of particular interest for a constant Brans-Dicke parameter, the
de Sitter space has also been investigated.Comment: 9 page
Role of Mineralogy, Mineral Chemistry and Geochemistry in Mineral Processing : A case study for High Phosphorous manganese ores of Nishikhal, South Orissa, India
Conformable manganese ore bands are present in the khond-alite suite of rocks belonging to the Eastern Ghats Complex of South Orissa,India. The ores cart be classified as high-grade, siliceous and ferruginous. Cryptomelane, romanechite, pyrolusite, jacobsite, hausmannite, braunite, lithiophorite, birnessite and pyrophanite represent the manganese minerals. Goethite, limonite, graphite, hematite,
magnetite are the associated opaque gangue minerals while quartz,orthoclase, hyalophane, garnet, kaolinite, apatite, collophane,. fibrolite,zircon, biotite and muscovite are the silicate gangue minerals recorded in these ores.
Optical microscopic and Electron Probe Microanalysis studies revealed that the phosphorous, in these ores, present in the form of (i) apatite inclusions within qua-rtz, orthoclase and garnet, (ii) amorphous calcium phos-phate (collophane) within the voids of garnet, (iii) ads-orbed component within the manganese oxide and silicate phases as well as in the iron oxide phase (goethite) Geochemical studies indicated that high amount of phos-phorous is linked with ferruginous manganese ores. Regression analysis of the geochemical data suggests a strong positive correlation between P-Fe and P-Mn. Magnetic separation studies on low- and off- grade bulk manganese samples, indicated that the phosphorous contributed by apatite is relatively low (4.44 to 17.76%)
compared to the phosphorous held in adsorption(82.24 to 95.56%), while the contribution of phosphorous by collophane is insignificant.The above studies confirm that the association of phosphorous in Nishikhal ores is very complex. Since most of the phosphorous is in adsorption, these low and off grade ores are expected to respond well
to dephosphorisation by reduction roasting followed by magnetic separation or roast alkali leaching method
Ab initio determination of the lifetime of the state f or by relativistic many-body theory
Relativistic coupled-cluster(RCC) theory has been employed to calculate the
life time of the state of single ionized lead() to an
accurac y of 3% and compared with the corresponding value obtained using second
order r elativistic many-body perturbation theory(RMBPT). This is one of the
very few ap plications of this theory to excited state properties of heavy
atomic systems. C ontributions from the different electron correlation effects
are given explicitl y
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