9,553 research outputs found

    Black Hole Entropy in the presence of Chern-Simons Terms

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    We derive a formula for the black hole entropy in theories with gravitational Chern-Simons terms, by generalizing Wald's argument which uses the Noether charge. It correctly reproduces the entropy of three-dimensional black holes in the presence of Chern-Simons term, which was previously obtained via indirect methods.Comment: v2: 12 pages, added reference

    Search For A Permanent Electric Dipole Moment Using Atomic Indium

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    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

    Spectacular Role of Electron Correlation in the Hyperfine Interactions in 2D5/2^2D_{5/2} States in Alkaline Earth Ions

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    The low-lying n(=3,4,5)d 2D5/2^2D_{5/2} 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

    Accurate estimations of circumstellar and interstellar lines of quadruply ionized vanadium using the coupled cluster approach

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    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, V4+V^{4+}. 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

    Transition Properties of Low Lying States in Atomic Indium

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    We present here the results of our relativistic many-body calculations of various properties of the first six low-lying excited states of indium. The calculations were performed using the relativistic coupled-cluster method in the framework of the singles, doubles and partial triples approximation. We obtain a large lifetime ~10s for the [4p^6]5s^2 5p_{3/2} state, which had not been known earlier. Our precise results could be used to shed light on the reliability of the lifetime measurements of the excited states of atomic indium that we have considered in the present work.Comment: 6 pages, 1 figure and 3 table

    Design and development of FRP mobile fish vending trolley for hygienic fish marketing

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    A mobile fish vending trolley has been designed and developed by Indian Council of Agricultural Research (ICAR) - All India Coordinated Research Project on Plasticulture Engineering and Technology (AICRP on PET) centre at ICAR-Central Institute of Freshwater Aquaculture (ICAR-CIFA), Bhubaneswar to aid the fisher folks for vending their fish harvests in hygienic condition. The unique selling proposition (USP) of the vending unit is its unibody design, where icebox for storing fish, 20 l capacity water storage tank for hand washing, tool box, fish cutting deck and waste collection chambers are integrated into the unit. The icebox can store 100 kg of fish in ice which can be sold in a single day by the fisher folks. The complete unit of mobile fish vending carriage is fabricated with fibre reinforced plastic (FRP), because of its high strength compared to other plastics, ease of fabrication and good insulation property of fiberglass (i.e. thermal conductivity= 0.04 w/mK at normal room temperature 25 ºC). The dimensions of the carriage unit is 4.0’x2’9”x2’6” in which half portion is dedicated for the insulated ice box and the remaining portion houses the fish cutting deck, waste collection chamber and tool box. This fish vending trolley would be a boon for the marginal fish vendors, who want to sell fish in a hygienic condition and to increase income generation potential by selling 100 kg fish in a day

    Evaluation of Boundary Shear Distribution in A Meandering Channel

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    Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

    Switching of the topologically trivial and non-trivial quantum phase transitions in compressed 1T-TiTe2: Experiments and Theory

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    We report the structural, vibrational and electrical transport properties up to 16 GPa of the 1T-TiTe2, a prominent layered 2D system, which is predicted to show a series of topologically trivial - nontrivial transitions under hydrostatic compression. We clearly show signatures of two iso-structural transition at 2 GPa and 4 GPa obtained from the minima in c/a ratio concomitant with the phonon linewidth anomalies of Eg and A1g modes at around the same pressures, providing strong indication of unusual electron-phonon coupling associated to these transitions. Resistivity presents nonlinear behavior over similar pressure ranges providing a strong indication of the electronic origin of these pressure driven isostructural transitions. Our data thus provide clear evidences of topological changes at A and L point of the Brillouin zone predicted to be present in the compressed 1T-TiTe2. Between 4 GPa and 8 GPa, the c/a ratio shows a plateau suggesting a transformation from an anisotropic 2D layer to a quasi 3D crystal network. First principles calculations suggest that the 2D to quasi 3D evolution without any structural phase transitions is mainly due to the increased interlayer Te-Te interactions (bridging) via the charge density overlap. In addition to the pressure dependent isostructural phase transitions, our data also evidences the occurrence of a first order structural phase transition from the trigonal (P-3m1) phase at higher pressures. We estimate the start of this structural phase transition to be 8 GPa and the symmetric of the new high-pressure phase to be monoclinic (C2/m).Comment: 22 pages, 11 Figures, 2 Table
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