2,090 research outputs found

    Molecular Fine Structure from Water Window X-rays

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    Evidence for Superfluidity in a Resonantly Interacting Fermi Gas

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    We observe collective oscillations of a trapped, degenerate Fermi gas of 6^6Li atoms at a magnetic field just above a Feshbach resonance, where the two-body physics does not support a bound state. The gas exhibits a radial breathing mode at a frequency of 2837(05) Hz, in excellent agreement with the frequency of νH≡10νxνy/3=2830(20)\nu_H\equiv\sqrt{10\nu_x\nu_y/3}=2830(20) Hz predicted for a {\em hydrodynamic} Fermi gas with unitarity limited interactions. The measured damping times and frequencies are inconsistent with predictions for both the collisionless mean field regime and for collisional hydrodynamics. These observations provide the first evidence for superfluid hydrodynamics in a resonantly interacting Fermi gas.Comment: 5 pages, ReVTeX4, 2 eps figs. Resubmitted to PRL in response to referees' comments. Title and abstract changed. Corrected error in Table 1, atom numbers for 0.33 TF and 0.5 TF data were interchanged. Corrected typo in ref 3. Added new figure of damping time versus temperatur

    Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic Motion

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    We report on Kerr nonlinearity and dispersive optical bistability of a Fabry-Perot optical resonator due to the displacement of ultracold atoms trapped within. In the driven resonator, such collective motion is induced by optical forces acting upon up to 10510^5 87^{87}Rb atoms prepared in the lowest band of a one-dimensional intracavity optical lattice. The longevity of atomic motional coherence allows for strongly nonlinear optics at extremely low cavity photon numbers, as demonstrated by the observation of both branches of optical bistability at photon numbers below unity.Comment: 4 pages, 3 figures. Modifed following reviewer comment

    Universal Approach to Optimal Photon Storage in Atomic Media

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    We present a universal physical picture for describing storage and retrieval of photon wave packets in a Lambda-type atomic medium. This physical picture encompasses a variety of different approaches to pulse storage ranging from adiabatic reduction of the photon group velocity and pulse-propagation control via off-resonant Raman fields to photon-echo based techniques. Furthermore, we derive an optimal control strategy for storage and retrieval of a photon wave packet of any given shape. All these approaches, when optimized, yield identical maximum efficiencies, which only depend on the optical depth of the medium.Comment: 4 pages, 3 figures. V2: major changes in presentation (title, abstract, main text), simplification of derivations, new references. V3: minor changes - final version as published in Phys. Rev. Let

    THE INTERACTION OF TRITIUM WITH POLYMERIC MATERIALS

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    Are juries representative? An examination of the representativeness of jury panels in Hamilton County Tennessee

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    Under the United States Constitution, a defendant has the right to a trial by jury composed of his or her peers. The intent is for the chosen jurors to be representative of the defendant‟s community. This study examined whether the jury panels in State Court in Hamilton County, Tennessee are representative of the community. A sample of 375 citizens who appeared for jury duty were given a questionnaire that measures the same demographic characteristics that appear in the United States 2010 Census. The results show that compared with the Census, the jury panels are not representative of the citizens who live in Hamilton County. Namely, the jury panels consist of a higher percentage of Whites, males, and citizens with higher levels of education and income. Similar results were found in a sample collected nearly a decade ago when compared with the U. S. Census. The findings from the present study indicate that jury panels may not be demographically representative, and therefore, not composed of a fair cross section of the community. This is the first known study to examine the representativeness of juries. The legal implications and suggestions for future research will be discussed
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