3,052 research outputs found

    A First Experimental Limit on In-matter Torsion from Neutron Spin Rotation in Liquid He-4

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    We report the first experimental upper bound to our knowledge on possible in-matter torsion interactions of the neutron from a recent search for parity violation in neutron spin rotation in liquid He-4. Our experiment constrains a coefficient ζ\zeta consisting of a linear combination of parameters involving the time components of the torsion fields TμT^\mu and AμA^\mu from the nucleons and electrons in helium which violates parity. We report an upper bound of ∣ζ∣<9.1x10−23|\zeta|<9.1x10^{-23} GeV at 68% confidence level and indicate other physical processes that could be analyzed to constrain in-matter torsion.Comment: 12 pages, typo correcte

    Seals at sea: modelling seal distribution in the German bight based on aerial survey data

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    The Wadden Sea is an important habitat for harbour seals and grey seals. They regularly haul-out on sandbanks and islands along the coast. Comparably little is known about the time seals spend at sea and how they use the remainder of the North Sea. Yet, human activity in offshore waters is increasing and information on seal distribution in the North Sea is crucial for conservation and management. Aerial line transect surveys were conducted in the German bight from 2002 to 2007 to investigate the distribution and abundance of marine mammals. Distance sampling methodology was combined with density surface modelling for a spatially explicit analysis of seal distribution in the German North Sea. Depth and distance to coast were found to be relevant predictor variables for seal density. Density surface modelling allowed for a depiction of seal distribution in the study area as well as an abundance estimate. This is the first study to use aerial survey data to develop a density surface model (DSM) for a spatially explicit distribution estimate of seals at se

    Quellenforschung Und Fiktive Strukturen

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    Paper delivered before the Germanic Section of The Modern Language Association in Chicago on December 28, 196

    CPT and Lorentz-invariance violation

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    The largest gap in our understanding of nature at the fundamental level is perhaps a unified description of gravity and quantum theory. Although there are currently a variety of theoretical approaches to this question, experimental research in this field is inhibited by the expected Planck-scale suppression of quantum-gravity effects. However, the breakdown of spacetime symmetries has recently been identified as a promising signal in this context: a number of models for underlying physics can accommodate minuscule Lorentz and CPT violation, and such effects are amenable to ultrahigh-precision tests. This presentation will give an overview of the subject. Topics such as motivations, the SME test framework, mechanisms for relativity breakdown, and experimental tests will be reviewed. Emphasis is given to observations involving antimatter.Comment: 6 page

    Initialization by measurement of a two-qubit superconducting circuit

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    We demonstrate initialization by joint measurement of two transmon qubits in 3D circuit quantum electrodynamics. Homodyne detection of cavity transmission is enhanced by Josephson parametric amplification to discriminate the two-qubit ground state from single-qubit excitations non-destructively and with 98.1% fidelity. Measurement and postselection of a steady-state mixture with 4.7% residual excitation per qubit achieve 98.8% fidelity to the ground state, thus outperforming passive initialization.Comment: 5 pages, 4 figures, and Supplementary Information (7 figures, 1 table
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