19,930 research outputs found

    Heat conduction in 2D strongly-coupled dusty plasmas

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    We perform non-equilibrium simulations to study heat conduction in two-dimensional strongly coupled dusty plasmas. Temperature gradients are established by heating one part of the otherwise equilibrium system to a higher temperature. Heat conductivity is measured directly from the stationary temperature profile and heat flux. Particular attention is paid to the influence of damping effect on the heat conduction. It is found that the heat conductivity increases with the decrease of the damping rate, while its magnitude agrees with previous experimental measurement.Comment: 4 pages, 2 figures, presented in SCCS2008 conferenc

    Dynamical evolution of a scalar field coupling to Einstein's tensor in the Reissner-Nordstr\"{o}m black hole spacetime

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    We study the dynamical evolution of a scalar field coupling to Einstein's tensor in the background of Reissner-Nordstr\"{o}m black hole. Our results show that the the coupling constant η\eta imprints in the wave dynamics of a scalar perturbation. In the weak coupling, we find that with the increase of the coupling constant η\eta the real parts of the fundamental quasinormal frequencies decrease and the absolute values of imaginary parts increase for fixed charge qq and multipole number ll. In the strong coupling, we find that for l≠0l\neq0 the instability occurs when η\eta is larger than a certain threshold value ηc\eta_c which deceases with the multipole number ll and charge qq. However, for the lowest l=0l=0, we find that there does not exist such a threshold value and the scalar field always decays for arbitrary coupling constant.Comment: 11 pages, 6 figures, accepted for publication in Phys Rev

    Dynamical evolution of scalar perturbation in Ho\v{r}ava-Lifshitz black-hole spacetimes

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    We study the dynamical evolution of a massless scalar perturbation in the Ho\v{r}ava-Lifshitz black-hole spacetimes with the coupling constants λ=1/3\lambda={1/3}, λ=1/2\lambda={1/2} and λ=3\lambda=3, respectively. Our calculation shows that, for the three cases, the scalar perturbations decay without any oscillation in which the decay rate imprints the parameter of the Ho\v{r}ava-Lifshitz black hole. The results are quite different from those in the Schwarzschild AdS black hole and can help us understand more about the Ho\v{r}ava-Lifshitz gravity.Comment: 14 pages, 5 figure

    The Role of Phase Space in Complex Fragment Emission from Low to Intermediate Energies

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    The experimental emission probabilities of complex fragments by low energy compound nuclei and their dependence upon energy and atomic number are compared to the transition state rates. Intermediate-mass-fragment multiplicity distributions for a variety of reactions at intermediate energies are shown to be binomial and thus reducible at all measured transverse energies. From these distributions a single binary event probability can be extracted which has a thermal dependence. A strong thermal signature is also found in the charge distributions. The n-fold charge distributions are reducible to the 1-fold charge distributions through a simple scaling dictated by fold number and charge conservation.Comment: 15 pages, TeX type, psfig, also available at http://csa5.lbl.gov/moretto/ps/brazil.ps, to appear in Proceedings of the 1st International Conference on Nuclear Dynamics at Long and Short Distances, April 8-12, 1996, Angra dos Reis, Brazi

    Dirac quasinormal frequencies of Reissner-Nordstr\"om black hole in Anti-de Sitter spacetime

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    The quasinormal modes (QNMs) of Dirac field perturbations of a Reissner-Nordstr\"om black hole in an asymptotically Anti-de Sitter spacetime are investigated. We find that both the real and imaginary parts of the fundamental quasinormal frequencies for large black holes are the linear functions of the Hawking temperature, and the slope of the lines for the real parts decreases while that for the magnitude of the imaginary parts increases as the black hole charge increases. According to the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence, the fact shows that different charge presents different time scale in three-dimensional CFT. Another interesting result is that the quasinormal frequencies become evenly spaced for high overtone number, and in the spacing expressions the real part decreases while the magnitude of the imaginary part increases as the charge increases. We also study the relation between quasinormal frequencies and angular quantum number and find that the real part increases while the magnitude of the imaginary part decreases as the angular quantum number increases.Comment: 16 pages, 4 figure

    Tilt-Induced Anisotropic to Isotropic Phase Transition at ν=5/2\nu = 5/2

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    A modest in-plane magnetic field \Bpar\ is sufficient to destroy the fractional quantized Hall states at ν=5/2\nu = 5/2 and 7/2 and replace them with anisotropic compressible phases. Remarkably, we find that at larger \Bpar\ these anisotropic phases can themselves be replaced by isotropic compressible phases reminiscent of the composite fermion fluid at ν=1/2\nu = 1/2. We present strong evidence that this transition is a consequence of the mixing of Landau levels from different electric subbands. We also report surprising dependences of the energy gaps at ν=5/2\nu = 5/2 and 7/3 on the width of the confinement potential.Comment: Accepted by Phys. Rev. Lett. This is a final version with rewritten introduction and modified figure
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