91,873 research outputs found

    Two-Photon Pathway to Ultracold Ground State Molecules of 23^{23}Na40^{40}K

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    We report on high-resolution spectroscopy of ultracold fermionic \nak~Feshbach molecules, and identify a two-photon pathway to the rovibrational singlet ground state via a resonantly mixed \Bcres intermediate state. Photoassociation in a 23^{23}Na-40^{40}K atomic mixture and one-photon spectroscopy on \nak~Feshbach molecules reveal about 20 vibrational levels of the electronically excited \ctrip state. Two of these levels are found to be strongly perturbed by nearby \Bsing states via spin-orbit coupling, resulting in additional lines of dominant singlet character in the perturbed complex {B1Πv=4c3Σ+v=25{\rm B}^1\Pi |v{=}4\rangle {\sim} {\rm c}^3\Sigma^+ | v{=}25\rangle}, or of resonantly mixed character in {B1Πv=12c3Σ+v=35{\rm B}^1\Pi | v{=}12 \rangle {\sim}{\rm c}^3\Sigma^+ | v{=}35 \rangle}. The dominantly singlet level is used to locate the absolute rovibrational singlet ground state X1Σ+v=0,J=0{\rm X}^1\Sigma^+ | v{=}0, J{=}0 \rangle via Autler-Townes spectroscopy. We demonstrate coherent two-photon coupling via dark state spectroscopy between the predominantly triplet Feshbach molecular state and the singlet ground state. Its binding energy is measured to be 5212.0447(1) \cm, a thousand-fold improvement in accuracy compared to previous determinations. In their absolute singlet ground state, \nak~molecules are chemically stable under binary collisions and possess a large electric dipole moment of 2.722.72 Debye. Our work thus paves the way towards the creation of strongly dipolar Fermi gases of NaK molecules.Comment: 23 pages, 8 figure

    Ultracold Dipolar Gas of Fermionic 23^{23}Na40^{40}K Molecules in their Absolute Ground State

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    We report on the creation of an ultracold dipolar gas of fermionic 23^{23}Na40^{40}K molecules in their absolute rovibrational and hyperfine ground state. Starting from weakly bound Feshbach molecules, we demonstrate hyperfine resolved two-photon transfer into the singlet X1Σ+v=0,J=0{\rm X}^1\Sigma^+ |v{=}0,J{=}0\rangle ground state, coherently bridging a binding energy difference of 0.65 eV via stimulated rapid adiabatic passage. The spin-polarized, nearly quantum degenerate molecular gas displays a lifetime longer than 2.5 s, highlighting NaK's stability against two-body chemical reactions. A homogeneous electric field is applied to induce a dipole moment of up to 0.8 Debye. With these advances, the exploration of many-body physics with strongly dipolar Fermi gases of 23^{23}Na40^{40}K molecules is in experimental reach.Comment: 5 pages, 5 figure

    16 x 25 Ge:Ga Detector Arrays for FIFI LS

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    We are developing two-dimensional 16 x 25 pixel detector arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-infrared astronomy from SOFIA. The arrays, based on earlier 5 x 5 detector arrays used on the KAO, will be for our new instrument, the Far Infrared Field Imaging Line Spectrometer (FIFI LS). The unstressed Ge:Ga detector array will cover the wavelength range from 40 to 120 microns, and the stressed Ge:Ga detector array from 120 to 210 microns. The detector arrays will be operated with multiplexed integrating amplifiers with cryogenic readout electronics located close to the detector arrays. The design of the stressed detector array and results of current measurements on several prototype 16 pixel linear arrays are reported. They demonstrate the feasibility of the current concept. ***This paper does not include Figures due to astro-ph size limitations. Please download entire file at http://fifi-ls.mpe-garching.mpg.de/spie.det.ps.gz ***Comment: 8 pages, SPIE Proceedings, Astronomical Telescopes and Instrumentation 200

    The quantization of the chiral Schwinger model based on the BFT-BFV formalism II

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    We apply an improved version of Batalin-Fradkin-Tyutin (BFT) Hamiltonian method to the a=1 chiral Schwinger Model, which is much more nontrivial than the a>1.one.Furthermore,throughthepathintegralquantization,wenewlyresolvetheproblemofthenontrivial one. Furthermore, through the path integral quantization, we newly resolve the problem of the non-trivial \deltafunctionaswellasthatoftheunwantedFourierparameter function as well as that of the unwanted Fourier parameter \xi$ in the measure. As a result, we explicitly obtain the fully gauge invariant partition function, which includes a new type of Wess-Zumino (WZ) term irrelevant to the gauge symmetry as well as usual WZ action.Comment: 17 pages, To be published in J. Phys.

    Protein transduction: A novel tool for tissue regeneration

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    Tissue regeneration in humans is limited and excludes vitals organs like heart and brain. Transformation experiments with oncogenes like T antigen have shown that retrodifferentiation of the respective cells is possible but hard to control. To bypass the risk of cancer formation a protein therapy approach has been developed. The transient delivery of proteins rather than genes could still induce terminallydifferentiated cells to reenter the cell cycle. This approach takes advantage of proteintransducing domains that mediate the transfer of cargo proteins into cells. The goal of this brief review is to outline the basics of protein transduction and to discuss potential applications for tissue regeneration

    Generalized BFT Formalism of Electroweak Theory in the Unitary Gauge

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    We systematically embed the SU(2)×\timesU(1) Higgs model in the unitary gauge into a fully gauge-invariant theory by following the generalized BFT formalism. We also suggest a novel path to get a first-class Lagrangian directly from the original second-class one using the BFT fields.Comment: 14 pages, Latex, no figure

    Observation of b2_2 symmetry vibrational levels of the SO2_2 \tilde{\mbox{C}} 1^1B2_2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

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    The C~\mathrm{\tilde{C}} 1^1B2_2 state of SO2_2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2_2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X~\mathrm{\tilde{X}} state are vibronically forbidden. We use IR-UV double resonance to observe the b2_2 vibrational levels of the C~\mathrm{\tilde{C}} state below 1600 cm1^{-1} of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong cc-axis Coriolis interactions between levels of a1_1 and b2_2 vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C~\mathrm{\tilde{C}} electronic state

    Does three-tangle properly quantify the three-party entanglement for Greenberger-Horne-Zeilinger-type states?

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    Some mixed states composed of only GHZ states can be expressed in terms of only W-states. This fact implies that such states have vanishing three-tangle. One of such rank-3 states, ΠGHZ\Pi_{GHZ}, is explicitly presented in this paper. These results are used to compute analytically the three-tangle of a rank-4 mixed state σ\sigma composed of four GHZ states. This analysis with considering Bloch sphere S16S^{16} of d=4d=4 qudit system allows us to derive the hyper-polyhedron. It is shown that the states in this hyper-polyhedron have vanishing three-tangle. Computing the one-tangles for ΠGHZ\Pi_{GHZ} and σ\sigma, we prove the monogamy inequality explicitly. Making use of the fact that the three-tangle of ΠGHZ\Pi_{GHZ} is zero, we try to explain why the W-class in the whole mixed states is not of measure zero contrary to the case of pure states.Comment: 10 pages, no figure V2: new calculational results are included. 11 pages: V3 accepted in the Rapid Communication of PRA, 4 pages (two column

    Rotating Black Holes at Future Colliders. III. Determination of Black Hole Evolution

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    TeV scale gravity scenario predicts that the black hole production dominates over all other interactions above the scale and that the Large Hadron Collider will be a black hole factory. Such higher dimensional black holes mainly decay into the standard model fields via the Hawking radiation whose spectrum can be computed from the greybody factor. Here we complete the series of our work by showing the greybody factors and the resultant spectra for the brane localized spinor and vector field emissions for arbitrary frequencies. Combining these results with the previous works, we determine the complete radiation spectra and the subsequent time evolution of the black hole. We find that, for a typical event, well more than half a black hole mass is emitted when the hole is still highly rotating, confirming our previous claim that it is important to take into account the angular momentum of black holes.Comment: typoes in eqs(82)-(84) corrected; version to appear in Phys. Rev. D; references and a footnote added; same manuscript with high resolution embedded figures available on http://www.gakushuin.ac.jp/univ/sci/phys/ida/paper
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