5,831 research outputs found

    Quantum sensing

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    "Quantum sensing" describes the use of a quantum system, quantum properties or quantum phenomena to perform a measurement of a physical quantity. Historical examples of quantum sensors include magnetometers based on superconducting quantum interference devices and atomic vapors, or atomic clocks. More recently, quantum sensing has become a distinct and rapidly growing branch of research within the area of quantum science and technology, with the most common platforms being spin qubits, trapped ions and flux qubits. The field is expected to provide new opportunities - especially with regard to high sensitivity and precision - in applied physics and other areas of science. In this review, we provide an introduction to the basic principles, methods and concepts of quantum sensing from the viewpoint of the interested experimentalist.Comment: 45 pages, 13 figures. Submitted to Rev. Mod. Phy

    Shape fluctuations and elastic properties of two-component bilayer membranes

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    The elastic properties of two-component bilayer membranes are studied using a coarse grain model for amphiphilic molecules. The two species of amphiphiles considered here differ only in their length. Molecular Dynamics simulations are performed in order to analyze the shape fluctuations of the two-component bilayer membranes and to determine their bending rigidity. Both the bending rigidity and its inverse are found to be nonmonotonic functions of the mole fraction xBx_{\rm B} of the shorter B-amphiphiles and, thus, do not satisfy a simple lever rule. The intrinsic area of the bilayer also exhibits a nonmonotonic dependence on xBx_{\rm B} and a maximum close to xB≃1/2x_{\rm B} \simeq 1/2.Comment: To appear on Europhysics Letter

    Forward-backward asymmetry of photoemission in C60_{60} excited by few-cycle laser pulses

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    We theoretically analyze angle-resolved photo-electron spectra (ARPES) generated by the interaction of C60_{60} with intense, short laser pulses. In particular, we focus on the impact of the carrier-envelope phase (CEP) onto the angular distribution. The electronic dynamics is described by time-dependent density functional theory, and the ionic background of \csixty is approximated by a particularly designed jellium model. Our results show a clear dependence of the angular distributions onto the CEP for very short pulses covering only very few laser cycles, which disappears for longer pulses. For the specific laser parameters used in a recent experiments, a very good agreement is obtained. Furthermore, the asymmetry is found to depend on the energy of the emitted photoelectrons. The strong influence of the angular asymmetry of electron emission onto the CEP and pulse duration suggests to use this sensitivity as a means to analyze the structure of few-cycle laser pulses.Comment: 8 pages, 6 figure

    A New Parameter Set for the Relativistic Mean Field Theory

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    Subtracting the Strutinsky shell corrections from the selfconsistent energies obtained within the Relativistic Mean Field Theory (RMFT) we have got estimates for the macroscopic part of the binding energies of 142 spherical even-even nuclei. By minimizing their root mean square deviations from the values obtained with the Lublin-Srasbourg Drop (LSD) model with respect to the nine RMFT parameters we have found the optimal set (NL4). The new parameters reproduce also the radii of these nuclei with an accuracy comparable with that obtained with the NL1 and NL3 sets.Comment: Semiar given at the 10th Nuclear Physics Workshop in Kazimierz, Poland, Sep. 24-28, 200

    Generalized Mayer-Vietoris sequences in algebraic K-theory

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    AbstractLong exact sequences of algebraic K-groups for certain kinds of multiple pullback rings are constructed, with special emphasis on Dedekind-like rings. In the case where excision holds they reduce to the usual Mayer-Vietoris sequences. These sequences are then used to obtain information about the K-groups of integral group rings of abelian groups of square-free order; about certain rings of integers in number fields; and about the coordinate ring of n lines in the plane

    Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 2. tt-channel Process

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    We present a study of the tt-channel mode of single top quark production at the upgraded Tevatron ppˉp\bar{p} collider, including the next-to-leading order (NLO) QCD corrections to the production and the decay of a single top quark. The narrow width approximation was adopted in order to preserve the spin of the top quark in its production and decay. We discuss the effects of different O(αs)O(\alpha_s) contributions on the inclusive cross section as well as various kinematic distributions after imposing the relevant cuts to select tt-channel single top signal events.Comment: 46 pages, 47 figures. One typo in LaTeX source file is correcte
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