49,082 research outputs found

    Rotational correlation and dynamic heterogeneity in a kinetically constrained lattice gas

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    We study dynamical heterogeneity and glassy dynamics in a kinetically constrained lattice gas model which has both translational and rotational degrees of freedom. We find that the rotational diffusion constant tracks the structural relaxation time as density is increased whereas the translational diffusion constant exhibits a strong decoupling. We investigate distributions of exchange and persistence times for both the rotational and translational degrees of freedom and compare our results on the distributions of rotational exchange times to recent single molecule studies.Comment: 7 pages, 5 figure

    Compact and Broadband Microstrip-Line-Fed Modified Rhombus Slot Antenna

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    The printed microstrip-line-fed broadband rhombus slot antenna is investigated in this paper. With the use of the offset microstrip feed line and the corner-truncated protruded ground plane, the bandwidth enhancement and the slot size reduction for the proposed slot antenna can be obtained. The experimental results demonstrate that the impedance bandwidth for 10 dB return loss reaches 5210 MHz (108.2%, 2210-7420 MHz), which is about 2.67 times of a conventional microstrip-line-fed rhombus slot antenna. This bandwidth can provide with the wireless communication services operating in wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) bands. Under the use of the protruded ground plane, the slot size can be reduced by about 52%. Details of simulated and measured results are presented and discussed

    Simple Scheme for Efficient Linear Optics Quantum Gates

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    We describe the construction of a conditional quantum control-not (CNOT) gate from linear optical elements following the program of Knill, Laflamme and Milburn [Nature {\bf 409}, 46 (2001)]. We show that the basic operation of this gate can be tested using current technology. We then simplify the scheme significantly.Comment: Problems with PDF figures correcte

    The induced representations of Brauer algebra and the Clebsch-Gordan coefficients of SO(n)

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    Induced representations of Brauer algebra Df(n)D_{f}(n) from Sf1×Sf2S_{f_{1}}\times S_{f_{2}} with f1+f2=ff_{1}+f_{2}=f are discussed. The induction coefficients (IDCs) or the outer-product reduction coefficients (ORCs) of Sf1×Sf2Df(n)S_{f_{1}}\times S_{f_{2}}\uparrow D_{f}(n) with f4f\leq 4 up to a normalization factor are derived by using the linear equation method. Weyl tableaus for the corresponding Gel'fand basis of SO(n) are defined. The assimilation method for obtaining CG coefficients of SO(n) in the Gel'fand basis for no modification rule involved couplings from IDCs of Brauer algebra are proposed. Some isoscalar factors of SO(n)SO(n1)SO(n)\supset SO(n-1) for the resulting irrep [λ1, λ2, λ3, λ4,0˙][\lambda_{1},~\lambda_{2},~ \lambda_{3},~\lambda_{4},\dot{0}] with $\sum\limits_{i=1}^{4}\lambda_{i}\leq .Comment: 48 pages latex, submitted to Journal of Phys.

    Microscopic origin of the next generation fractional quantum Hall effect

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    Most of the fractions observed to date belong to the sequences ν=n/(2pn±1)\nu=n/(2pn\pm 1) and ν=1n/(2pn±1)\nu=1-n/(2pn\pm 1), nn and pp integers, understood as the familiar {\em integral} quantum Hall effect of composite fermions. These sequences fail to accommodate, however, many fractions such as ν=4/11\nu=4/11 and 5/13, discovered recently in ultra-high mobility samples at very low temperatures. We show that these "next generation" fractional quantum Hall states are accurately described as the {\em fractional} quantum Hall effect of composite fermions

    An Ultra-fast DOA Estimator with Circular Array Interferometer Using Lookup Table Method

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    The time-consuming phase ambiguity resolution makes the uniform circular array (UCA) interferometer not suitable for real-time direction-of-arrival (DOA) estimation. This paper introduces the lookup table (LUT) method to solve this problem. The key of the method is that we look up the ambiguity numbers instead of the eventual DOA from the table, and then the DOA is obtained by relatively small amount of calculation. This makes it possible that we are able to shrink the table size while maintain the DOA estimation accuracy. The table addresses cover all possible measured phase differences (PDs), which enables the method to be free of spatial scanning. Moreover, without adding frequency index to the lookup table, the estimator can realize wideband application. As an example, a field-programmable gate array (FPGA) based DOA estimator with the estimation time of 180 ns is presented, accompanied by the measured results. This method possesses the advantages of ultra-high speed, high accuracy and low memory usage

    A burst from the direction of UZ Fornacis with XMM-Newton

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    The XMM-Newton pointing towards the magnetic cataclysmic variable UZ For finds the source to be a factor > 10^3 fainter than previous EXOSAT and ROSAT observations. The source was not detected for the majority of a 22 ksec exposure with the EPIC cameras, suggesting that the accretion rate either decreased, or stopped altogether. However a 1.1 ksec burst was detected from UZ For during the observation. Spectral fits favour optically thin, kT = 4.4 keV thermal emission. Detection of the burst by the on-board Optical Monitor indicates that this was most probably an accretion event. The 0.1-10 keV luminosity of 2.1 x 10^30 erg/s is typical for accretion shock emission from high state polars and would result from the potential energy release of ~ 10^16 g of gas. There is no significant soft excess due to reprocessing in the white dwarf atmosphere.Comment: 7 pages, 2 postscript figures, ApJL, in pres
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