3,869 research outputs found

    Measurement of the neutron electric dipole moment by crystal diffraction

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    An experiment using a prototype setup to search for the neutron electric dipole moment by measuring spin-rotation in a non-centrosymmetric crystal (quartz) was carried out to investigate statistical sensitivity and systematic effects of the method. It has been demonstrated that the concept of the method works. The preliminary result of the experiment is dn=(2.5±6.5)⋅10−24d_{\rm n}=(2.5\pm 6.5)\cdot 10^{-24} e⋅\cdot cm. The experiment showed that an accuracy of ∼2.5⋅10−26\sim 2.5\cdot 10^{-26} e⋅\cdot cm can be obtained in 100 days data taking, using available quartz crystals and neutron beams.Comment: 13 pages, 4 figure

    Momentum Distributions of Particles from Three--Body Halo Fragmentation: Final State Interactions

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    Momentum distributions of particles from nuclear break-up of fast three-body halos are calculated consistently, and applied to 11^{11}Li. The same two-body interactions between the three particles are used to calculate the ground state structure and the final state of the reaction processes. We reproduce the available momentum distributions from 11^{11}Li fragmentation, together with the size and energy of 11^{11}Li, with a neutron-core relative state containing a pp-state admixture of 20\%-30\%. The available fragmentation data strongly suggest an ss-state in 10^{10}Li at about 50 keV, and indicate a pp-state around 500 keV.Comment: 11 pages (RevTeX), 3 Postscript figures (uuencoded postscript file attached at the end of the LaTeX file). To be published in Phys. Rev.

    Experimental evidence for new symmetry axis of electromagnetic beams

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    The new symmetry axis of a well-behaved electromagnetic beam advanced in paper Physical Review A 78, 063831 (2008) is not purely a mathematical concept. The experimental result reported by Hosten and Kwiat in paper Science 319, 787 (2008) is shown to demonstrate the existence of this symmetry axis that is neither perpendicular nor parallel to the propagation axis.Comment: 10 pages and 3 figure

    The Effective Fragment Molecular Orbital Method for Fragments Connected by Covalent Bonds

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    We extend the effective fragment molecular orbital method (EFMO) into treating fragments connected by covalent bonds. The accuracy of EFMO is compared to FMO and conventional ab initio electronic structure methods for polypeptides including proteins. Errors in energy for RHF and MP2 are within 2 kcal/mol for neutral polypeptides and 6 kcal/mol for charged polypeptides similar to FMO but obtained two to five times faster. For proteins, the errors are also within a few kcal/mol of the FMO results. We developed both the RHF and MP2 gradient for EFMO. Compared to ab initio, the EFMO optimized structures had an RMSD of 0.40 and 0.44 {\AA} for RHF and MP2, respectively.Comment: Revised manuscrip

    Quasi-Chaplygin Systems and Nonholonimic Rigid Body Dynamics

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    We show that the Suslov nonholonomic rigid body problem can be regarded almost everywhere as a generalized Chaplygin system. Furthermore, this provides a new example of a multidimensional nonholonomic system which can be reduced to a Hamiltonian form by means of Chaplygin reducing multiplier. Since we deal with Chaplygin systems in the local sense, the invariant manifolds of the integrable examples are not necessary tori.Comment: minor changes, to appear in Letters in Mathematical Physic

    Universality of three-body systems in 2D: parametrization of the bound states energies

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    Universal properties of mass-imbalanced three-body systems in 2D are studied using zero-range interactions in momentum space. The dependence of the three-particle binding energy on the parameters (masses and two-body energies) is highly non-trivial even in the simplest case of two identical particles and a distinct one. This dependence is parametrized for ground and excited states in terms of {\itshape supercircles} functions in the most general case of three distinguishable particles.Comment: 3 pages, 1 figure, published versio
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