7,744 research outputs found
Transport coefficients of a mesoscopic fluid dynamics model
We investigate the properties of stochastic rotation dynamics
(Malevanets-Kapral method), a mesoscopic model used for simulating fluctuating
hydrodynamics. Analytical results are given for the transport coefficients. We
discuss the most efficient way of measuring the transport properties and obtain
excellent agreement between the theoretical and numerical calculations.Comment: 12 pages, 9 figures, submitted to J. Chem. Phy
Generalized Einstein or Green-Kubo relations for active biomolecular transport
For driven Markovian dynamics on a network of (biomolecular) states, the
generalized mobilities, i.e., the response of any current to changes in an
external parameter, are expressed by an integral over an appropriate
current-current correlation function and thus related to the generalized
diffusion constants. As only input, a local detailed balance condition is
required typically even valid for biomolecular systems operating deep in the
non-equilibrium regime.Comment: 4 page
Micromagnetic Simulation of Non Uniform Nanodots with Perpendicular Anisotropy
Multilayered Pt/[Co/Pt]/sub 5/ films were fabricated into patterned dots with diameters of 120 and 200 nm by laser interference lithography. Anomalous Hall effect (AHE) measurements were used on an array of dots to measure the switching field and the effects of reversal of an area with reduced anisotropy in the dot were also investigated by micromagnetic simulation. It was shown that a reduction in switching field is caused by an area of reduced anisotropy. The effect of various combinations of a reduction in anisotropy and/or exchange constant, and the size and shape of the area were also discussed in this paper
Dynamical Susceptibility in KDP-type Crysals above and below Tc II
The path probability method (PPM) in the tetrahedron-cactus approximation is
applied to the Slater-Takagi model with dipole-dipole interaction for
KH2PO4-type hydrogen-bonded ferroelectric crystals in order to derive a small
dip structure in the real part of dynamical susceptibility observed at the
transition temperature Tc. The dip structure can be ascribed to finite
relaxation times of electric dipole moments responsible for the first order
transition with contrast to the critical slowing down in the second order
transition. The light scattering intensity which is related to the imaginary
part of dynamical susceptibility is also calculated above and below the
transition temperature and the obtained central peak structure is consistent
with polarization fluctuation modes in Raman scattering experiments.Comment: 8 pages, 11 figure
Constraints on unparticle long range forces from big bang nucleosynthesis bounds on the variation of the gravitational coupling
We use big bang nucleosynthesis bounds on the variation of the gravitational
coupling to derive constraints on the strength of the deviation from the
gravitational inverse-square law due to tensor and vector unparticle exchange.Comment: 4 pages, 3 figures, change in the title and other minor changes to
match version published in Physical Review
Kinetically driven helix formation during the homopolymer collapse process
Using Langevin simulations, we find that simple 'generic' bead-and-spring
homopolymer chains in a sufficiently bad solvent spontaneously develop helical
order during the process of collapsing from an initially stretched
conformation. The helix formation is initiated by the unstable modes of the
straight chain, which drive the system towards a long-lived metastable
transient state. The effect is most pronounced if hydrodynamic interactions are
screened.Comment: 4 pages, 4 figure
Convergence of Rothe's method in Hölder spaces
summary:The convergence of Rothe’s method in Hölder spaces is discussed. The obtained results are based on uniform boundedness of Rothe’s approximate solutions in Hölder spaces recently achieved by the first author. The convergence and its rate are derived inside a parabolic cylinder assuming an additional compatibility conditions
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