43,018 research outputs found

    Weight function for the quantum affine algebra Uq(sl^3)U_q(\hat{sl}_3)

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    We give a precise expression for the universal weight function of the quantum affine algebra Uq(sl^3)U_q(\hat{sl}_3). The calculations use the technique of projecting products of Drinfeld currents on the intersections of Borel subalgebras.Comment: 28 page

    Three realizations of quantum affine algebra Uq(A2(2))U_q(A_2^{(2)})

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    In this article we establish explicit isomorphisms between three realizations of quantum twisted affine algebra Uq(A2(2))U_q(A_2^{(2)}): the Drinfeld ("current") realization, the Chevalley realization and the so-called RLLRLL realization, investigated by Faddeev, Reshetikhin and Takhtajan.Comment: 15 page

    Recurrent Coronal Jets Induced by Repetitively Accumulated Electric Currents

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    Three extreme-ultraviolet (EUV) jets recurred in about one hour on 2010 September 17 in the following magnetic polarity of active region 11106. The EUV jets were observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The Helioseismic and Magnetic Imager (HMI) on board SDO measured the vector magnetic field, from which we derive the magnetic flux evolution, the photospheric velocity field, and the vertical electric current evolution. The magnetic configuration before the jets is derived by the nonlinear force-free field (NLFFF) extrapolation. We derive that the jets are above a pair of parasitic magnetic bipoles which are continuously driven by photospheric diverging flows. The interaction drove the build up of electric currents that we indeed observed as elongated patterns at the photospheric level. For the first time, the high temporal cadence of HMI allows to follow the evolution of such small currents. In the jet region, we found that the integrated absolute current peaks repetitively in phase with the 171 A flux evolution. The current build up and its decay are both fast, about 10 minutes each, and the current maximum precedes the 171 A by also about 10 minutes. Then, HMI temporal cadence is marginally fast enough to detect such changes. The photospheric current pattern of the jets is found associated to the quasi-separatrix layers deduced from the magnetic extrapolation. From previous theoretical results, the observed diverging flows are expected to build continuously such currents. We conclude that magnetic reconnection occurs periodically, in the current layer created between the emerging bipoles and the large scale active region field. It induced the observed recurrent coronal jets and the decrease of the vertical electric current magnitude.Comment: 10 pages, 7 figures, accepted for publication in A&

    Spectroscopy of 87Sr^{87}\text{Sr} triplet Rydberg states

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    A combined experimental and theoretical spectroscopic study of high-nn, 30n100{30 \lesssim n \lesssim 100}, triplet S\text{S} and D\text{D} Rydberg states in 87Sr^{87}\text{Sr} is presented. 87Sr^{87}\text{Sr} has a large nuclear spin, I=9/2{I=9/2}, and at high-nn the hyperfine interaction becomes comparable to, or even larger than, the fine structure and singlet-triplet splittings which poses a considerable challenge both for precision spectroscopy and for theory. For high-nn S\text{S} states, the hyperfine shifts are evaluated non-perturbatively taking advantage of earlier spectroscopic data for the I=0{I=0} isotope 88Sr^{88}\text{Sr}, which results in good agreement with the present measurements. For the D\text{D} states, this procedure is reversed by first extracting from the present 87Sr^{87}\text{Sr} measurements the energies of the 3D1,2,3^{3}\text{D}_{1,2,3} states to be expected for isotopes without hyperfine structure (88Sr^{88}\text{Sr}) which allows the determination of corrected quantum defects in the high-nn limit.Comment: 13 pages, 8 figure

    Possible Molecular States of DsDˉsD^{*}_s\bar{D}^{*}_s System and Y(4140)

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    The interpretation of Y(4140) as a DsDˉsD^{*}_s\bar{D}^{*}_s molecule is studied dynamically in the one boson exchange approach, where σ\sigma, η\eta and ϕ\phi exchange are included. Ten allowed DsDˉsD^{*}_s\bar{D}^{*}_s states with low spin parity are considered, we find that the JPC=0++J^{PC}=0^{++}, 1+1^{+-}, 0+0^{-+}, 2++2^{++} and 11^{--} DsDˉsD^{*}_s\bar{D}^{*}_s configurations are most tightly bound. We suggest the most favorable quantum numbers are JPC=0++J^{PC}=0^{++} for Y(4140) as a DsDˉsD^{*}_s\bar{D}^{*}_s molecule, however, JPC=0+J^{PC}=0^{-+} and 2++2^{++} can not be excluded. We propose to search for the 1+1^{+-} and 11^{--} partners in the J/ψηJ/\psi\eta and J/ψηJ/\psi\eta' final states, which is an important test of the molecular hypothesis of Y(4140) and the reasonability of our model. The 0++0^{++} BsBˉsB^{*}_s\bar{B}^{*}_s molecule is deeply bound, experimental search in the Υ(1S)ϕ\Upsilon(1S)\phi channel at Tevatron and LHC is suggested.Comment: 13 pages,2 figure

    Chaotic to ordered state transition of cathode-sheath instabilities in DC glow discharge plasmas

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    Transition from chaotic to ordered state has been observed during the initial stage of a discharge in a cylindrical dc glow discharge plasma. Initially it shows a chaotic behavior but increasing the discharge voltage changes the characteristics of the discharge glow and shows a period substraction of order 7 period \to 5 period \to3 period \to1 period i.e. the system goes to single mode through odd cycle subtraction. On further increasing the discharge voltage, the system goes through period doubling, like 1 period \to 2 period \to 4 period. On further increasing the voltage, the system goes to stable state without having any oscillations.Comment: chathode-sheath, instabilities, chaos, period-subtraction, bifurcation, dc-discharg

    Quantum state preparation and control of single molecular ions

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    Preparing molecules at rest and in a highly pure quantum state is a long standing dream in chemistry and physics, so far achieved only for a select set of molecules in dedicated experimental setups. Here, a quantum-limited combination of mass spectrometry and Raman spectroscopy is proposed that should be applicable to a wide range of molecular ions. Excitation of electrons in the molecule followed by uncontrolled decay and branching into several lower energy states is avoided. Instead, the molecule is always connected to rotational states within the electronic and vibrational ground-state manifold, while a co-trapped atomic ion provides efficient entropy removal and allows for extraction of information on the molecule. The outlined techniques might enable preparation, manipulation and measurement of a large multitude of molecular ion species with the same instrument, with applications including, but not limited to, precise determination of molecular properties and fundamental tests of physics.Comment: 12 pages, 2 figures, reformatted for resubmissio
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