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The hydrodynamic equations of dry active polar fluids (i.e., moving flocks without momentum conservation) are shown to imply giant number fluctuations. Specifically, the rms fluctuations $\sqrt {<(\delta N)^2>}$ of the number $N$ of active…

Statistical Mechanics · Physics 2019-05-22 John Toner

This paper is devoted to the mathematical analysis of a time-domain electromagnetic scattering by periodic structures which are known as diffraction gratings. The scattering problem is reduced equivalently into an initial-boundary value…

Analysis of PDEs · Mathematics 2016-04-05 Yixian Gao , Peijun Li

In cond-mat/0002074 Ricci-Tersenghi et al. find two linear regimes in the fluctuation-dissipation relation between density-density correlations and associated responses of the Frustrated Ising Lattice Gas. Here we show that this result does…

Statistical Mechanics · Physics 2009-11-07 A. de Candia , A. Coniglio

We present dynamic light scattering (DLS) measurements of soft polymethyl-methacrylate (PMMA) and polyacrylamide(PA) polymer gels prepared with trapped bodies (latex spheres or maghemite nanoparticles). We show that the anomalous…

Soft Condensed Matter · Physics 2015-06-10 Alvaro V. N. C. Teixeira , Erik Geissler , Pedro Licinio

This paper presents an analytical framework for the analysis of time-varying metal-based metamaterials. Concretely, we particularize the study to time-modulated metal-air interfaces embedded between two different semi-infinite media that…

Using Monte Carlo simulations we study the distributions of the 3-block mass $N_3$ in 4d, 5d, and 6d percolation systems. Because the probability of creating large 3-blocks in these dimensions is very small, we use a ``go with the winners''…

Disordered Systems and Neural Networks · Physics 2009-11-07 Gerald Paul , H. Eugene Stanley

A simple multifractal coarsening model is suggested that can explain the observed dynamical behavior of the fractal dimension in a wide range of coarsening fractal systems. It is assumed that the minority phase (an ensemble of droplets) at…

Disordered Systems and Neural Networks · Physics 2009-10-31 Avner Peleg , Baruch Meerson

The methods of determining the fractal dimension and irregularity scale in simulated galaxy catalogs and the application of these methods to the data of the 2dF and 6dF catalogs are analyzed. Correlation methods are shown to be correctly…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nikita Yu. Lovyagin

The fractal dimension of a surface allows its degree of roughness to be characterized quantitatively. However, limited effort is attempted to calculate the fractal dimension of surfaces computed from precisely known atomic coordinates from…

Mathematical Software · Computer Science 2024-03-12 Jonathan Yik Chang Ting , Andrew Thomas Agars Wood , Amanda Susan Barnard

A three-dimensional granular system fluidized by vertical container vibrations was studied using pulsed field gradient (PFG) NMR coupled with one-dimensional magnetic resonance imaging (MRI). The system consisted of mustard seeds vibrated…

Soft Condensed Matter · Physics 2009-11-10 Chao Huan , Xiaoyu Yang , D. Candela , R. W. Mair , R. L. Walsworth

The diffraction spectrum of coherent waves scattered from fractal supports is calculated exactly. The fractals considered are of the class generated iteratively by successive dilations and translations, and include generalizations of the…

Condensed Matter · Physics 2009-10-28 Daniel A. Hamburger-Lidar

We develop a mathematical framework to analyze electrochemical impedance spectra in terms of a distribution of diffusion times (DDT) for a parallel array of random finite-length Warburg (diffusion) or Gerischer (reaction-diffusion) circuit…

Chemical Physics · Physics 2018-03-21 Juhyun Song , Martin Z. Bazant

Diffusion Limited Aggregation (DLA) has served for forty years as a paradigmatic example for the creation of fractal growth patterns. In spite of thousands of references no exact result for the fractal dimension $D$ of DLA is known. In this…

Statistical Mechanics · Physics 2021-02-17 Eviatar B. Procaccia , Itamar Procaccia

Polymer adsorption on fractally rough walls of varying dimensionality is studied by renormalization group methods on hierarchical lattices. Exact results are obtained for deterministic walls. The adsorption transition is found continuous…

Statistical Mechanics · Physics 2007-05-23 G. Giugliarelli , A. L. Stella

Diffusion MRI (dMRI) provides contrast that reflect diffusing spins' interactions with microstructural features of biological systems, but its specificity remains limited due to the ambiguity of its relation to the underlying…

Medical Physics · Physics 2022-03-29 Jonas L. Olesen , Leif Østergaard , Noam Shemesh , Sune N. Jespersen

We consider single-phase flow in a fractured porous medium governed by Darcy's law with spatially varying hydraulic conductivity matrices in both bulk and fractures. The width-to-length ratio of a fracture is of the order of a small…

Analysis of PDEs · Mathematics 2024-02-01 Maximilian Hörl , Christian Rohde

Dissipative particle dynamics (DPD) is a novel particle method for mesoscale modeling of complex fluids. DPD particles are often thought to represent packets of real atoms, and the physical scale probed in DPD models are determined by the…

Chemical Physics · Physics 2016-10-18 R. Qiao , P. He

We study the anomalous scaling of the mass density measure of Lagrangian tracers in a compressible flow realized on the free surface on top of a three dimensional flow. The full two dimensional probability distribution of local stretching…

Chaotic Dynamics · Physics 2009-11-11 G. Boffetta , J. Davoudi , F. De Lillo

In this paper, a fractional generalization of the wave equation that describes propagation of damped waves is considered. In contrast to the fractional diffusion-wave equation, the fractional wave equation contains fractional derivatives of…

Mathematical Physics · Physics 2021-03-12 Yuri Luchko

In a recent letter (PRL,121,246101,2018), Sun et al. reported that combined MD simulation and sum frequency generation vibrational spectroscopy (SFG-VS) measurements led to conclusions of a broad and exponentially decaying orientational…

Chemical Physics · Physics 2019-09-04 Wei Gan , Ran-ran Feng , Hong-Fei Wang