3,731 research outputs found

    Complementarity of Entanglement and Interference

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    A complementarity relation is shown between the visibility of interference and bipartite entanglement in a two qubit interferometric system when the parameters of the quantum operation change for a given input state. The entanglement measure is a decreasing function of the visibility of interference. The implications for quantum computation are briefly discussed.Comment: Final version, to appear on IJMPC; minor revision

    Measurements of thermospheric response to auroral activities

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    The Joule heating produced by auroral electrojets and its thermospheric response can be studied by monitoring the thermospheric temperatures by optical methods; simultaneously, the concurrent auroral electrojet activities can be investigated by using geomagnetic records obtained from stations along a meridian close to the observation site of optical measurements. The measurements are reported of thermospheric response to auroral activities which were made at Albany (42.68 deg N, 73.82 deg W), New York on September 2, 1978 (UT) when an isolated substorm occured. The thermospheric temperatures were measured by using a high resolution Fabry-Perot interferometer that determines the line profiles of the (OI) 6300A line emission. The intensities and latitudinal positions of auroral electrojets were obtained by the analysis of magnetograms from the IMS Fort Churchill meridian chain stations

    Dynamic SU(2) Lattice Gauge Theory at Finite Temperature

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    The dynamic relaxation process for the (2+1)--dimensional SU(2) lattice gauge theory at critical temperature is investigated with Monte Carlo methods. The critical initial increase of the Polyakov loop is observed. The dynamic exponents θ\theta and zz as well as the static critical exponent β/ν\beta/\nu are determined from the power law behaviour of the Polyakov loop, the auto-correlation and the second moment at the early stage of the time evolution. The results are well consistent and universal short-time scaling behaviour of the dynamic system is confirmed. The values of the exponents show that the dynamic SU(2) lattice gauge theory is in the same dynamic universality class as the dynamic Ising model.Comment: 10 pages with 2 figure

    Structural and functional analysis of the baculovirus single-stranded DNA-binding protein LEF-3

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    AbstractThe single-stranded DNA-binding protein LEF-3 of Autographa californica multinucleocapsid nucleopolyhedrovirus consists of 385 amino acid residues, forms oligomers, and promotes Mg2+-independent unwinding of DNA duplexes and annealing of complementary DNA strands. Partial proteolysis revealed that the DNA-binding domain of LEF-3 is located within a central region (residues 28 to 326) that is relatively resistant to proteolysis. In contrast, the N-terminus (27 residues) and C-terminal portion (59 residues) are not involved in interaction with DNA and are readily accessible to proteolytic digestion. Circular dichroism analyses showed that LEF-3 is a folded protein with an estimated α-helix content of more than 40%, but it is structurally unstable and undergoes unfolding in aqueous solutions at temperatures near 50 °C. Unfolding eliminated the LEF-3 domains that are resistant to proteolysis and randomized the digestion pattern by trypsin. The structural transition was irreversible and was accompanied by the generation of high molecular weight (MW) complexes. The thermal treatment inhibited DNA-binding and unwinding activity of LEF-3 but markedly stimulated its annealing activity. We propose that the shift in LEF-3 activities resulted from the generation of the high MW protein complexes, that specifically stimulate the annealing of complementary DNA strands by providing multiple DNA-binding sites and bringing into close proximity the interacting strands. The unfolded LEF-3 was active in a strand exchange reaction suggesting that it could be involved in the production of recombination intermediates

    Complex Langevin Equation and the Many-Fermion Problem

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    We study the utility of a complex Langevin (CL) equation as an alternative for the Monte Carlo (MC) procedure in the evaluation of expectation values occurring in fermionic many-body problems. We find that a CL approach is natural in cases where non-positive definite probability measures occur, and remains accurate even when the corresponding MC calculation develops a severe ``sign problem''. While the convergence of CL averages cannot be guaranteed in principle, we show how convergent results can be obtained in three examples ranging from simple one-dimensional integrals over quantum mechanical models to a schematic shell model path integral.Comment: 19 pages, 10 PS figures embedded in tex

    miRNA-based rapid differentiation of purified neurons from hPSCs advancestowards quick screening for neuronal disease phenotypes in vitro

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    Obtaining differentiated cells with high physiological functions by an efficient, but simple and rapid differentiation method is crucial for modeling neuronal diseases in vitro using human pluripotent stem cells (hPSCs). Currently, methods involving the transient expression of one or a couple of transcription factors have been established as techniques for inducing neuronal differentiation in a rapid, single step. It has also been reported that microRNAs can function as reprogramming effectors for directly reprogramming human dermal fibroblasts to neurons. In this study, we tested the effect of adding neuronal microRNAs, miRNA-9/9*, and miR-124 (miR-9/9*-124), for the neuronal induction method of hPSCs using Tet-On-driven expression of the Neurogenin2 gene

    Observation of an energetic radiation burst from mountain-top thunderclouds

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    During thunderstorms on 2008 September 20, a simultaneous detection of gamma rays and electrons was made at a mountain observatory in Japan located 2770 m above sea level. Both emissions, lasting 90 seconds, were associated with thunderclouds rather than lightning. The photon spectrum, extending to 10 MeV, can be interpreted as consisting of bremsstrahlung gamma rays arriving from a source which is 60 - 130 m in distance at 90% confidence level. The observed electrons are likely to be dominated by a primary population escaping from an acceleration region in the clouds.Comment: 12 pages, 3 figures, accepted for publication in Physical Review Letter

    Temporal-offset dual-comb vibrometer with picometer axial precision

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    We demonstrate a dual-comb vibrometer where the pulses of one frequency-comb are split into pulse pairs. We introduce a delay between the two pulses of each pulse pair in front of the sample, and after the corresponding two consecutive reflections at the vibrating sample surface, the initially introduced delay is cancelled by a modified Sagnac geometry. The remaining phase difference between the two pulses corresponds to the change in the axial position of the surface during the two consecutive reflections. The Sagnac geometry reduces the effect of phase jitter since both pulses propagate through nearly the same optical path (in opposite directions), and spurious signals are eliminated by time gating. We determine the amplitude of a surface vibration on a surface-acoustic-wave device with an axial precision of 4 pm. This technique enables highly accurate determination of extremely small displacements.Comment: 22 pages, 5 figure

    Universal Short-time Behaviour of the Dynamic Fully Frustrated XY Model

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    With Monte Carlo methods we investigate the dynamic relaxation of the fully frustrated XY model in two dimensions below or at the Kosterlitz-Thouless phase transition temperature. Special attention is drawn to the sublattice structure of the dynamic evolution. Short-time scaling behaviour is found and universality is confirmed. The critical exponent θ\theta is measured for different temperature and with different algorithms.Comment: 18 pages, LaTeX, 8 ps-figure
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