The rupture dynamics of smectic bubbles supported on a capillary is studied by means of microsecond photography, and properties of the retracting films are quantitatively analyzed. The film material collects in a moving rim that follows the sphere shape. A constant edge velocity is reached instantly; it is proportional to the inverse square root of the film thickness and in reasonable quantitative agreement with model predictions. The rim constitution for thin and thick films differs. In thin (submicrometer) films, the rim undulates and decomposes into single droplets, while for thick films, it remains compact and straight, and a brim is formed. During rupture, the initial film thickness increases globally, despite the smectic layer structure. Then, the recession of the film edge is accompanied by undulations of the bubble surface in the micrometer range.

In experimental studies of a surface by an underdamped mechanical surface force probe the “tip” can return repeatedly to the same points in space. This causes a problem in using the experimental data to extract information about the surface structure. We propose an approach which allows one to extract the mesoscopic surface structure from dynamic experiments with underdamped systems. The approach was tested on numerically generated random fractal potentials and is applied to extract potential relief from real experimental data.

A fairly general form of the two-component (dark-dark) vector one-soliton solution of the integrable coupled nonlinear Schrödinger equation (Manakov model) with self-defocusing nonlinearity is obtained by using the Hirota method. It couples two dark components with the same envelope width, envelope speed, and envelope trough location using two complex arbitrary parameters not only in the envelope amplitude but also in the complex modulation. Although it has the freedom to change its pulse width without affecting its speed, it can also tune its grayness (depth of the pulse relative to background) without disturbing the envelope width and speed. The variations in peak power against the depth of localization of two dark components are investigated with and without a parametric restriction. The collision between many dark-dark vector solitons has also been studied by constructing a multisoliton solution with more free parameters.

We modify the directed-loop algorithm (DLA) to solve the problem that typically arises from large on-site interaction. The large on-site interaction is inevitable when one tries to simulate a Bose gas system in continuum by discretizing the space with small lattice spacings. While the efficiency of a straightforward application of DLA decreases as the mesh becomes finer, the performance of the new method does not depend on it except for the trivial factor due to the increase in the number of lattice points.

We present the master (i.e., unique) behavior of the squared capillary length—the so-called Sugden factor—as a function of the temperaturelike field along the critical isochore, asymptotically close to the gas-liquid critical point of about twenty (one-component) fluids. This master behavior is obtained using the scale dilatation of the relevant physical fields of the one-component fluids. The scale dilatation method introduces the fluid-dependent scale factors in a manner analog to the linear relations between physical fields and scaling fields needed by the renormalization theory applied to any physical system belonging to the Ising-like universality class. The master behavior for the Sugden factor satisfies hyperscaling. It can be asymptotically fitted by the leading terms of the theoretical crossover functions for the correlation length and the susceptibility in the homogeneous domain, recently obtained from massive renormalization in field theory. In the absence of corresponding estimation of the theoretical crossover functions for the interfacial tension, we define the range of the temperaturelike field where the master leading power law can be practically used to predict the singular behavior of the Sugden factor, in conformity with the theoretical description provided by the massive renormalization scheme within the extended asymptotic domain of the one-component fluid “subclass.”

Recent experiments [F. H. J. van der Heyden et al., Phys. Rev. Lett. 96, 224502 (2006)] of streaming currents in silica nanochannels with divalent ions report charge inversion, i.e., interfacial charges attracting counterions in excess of their own nominal charge, in conflict with existing theoretical and simulation results. We reveal the mechanism of charge inversion by using all-atomic molecular dynamics simulations. Our results show excellent agreement with experiments, both qualitatively and quantitatively. We further discuss the implications of our study for the general problem of ionic correlations in solutions as well as in regards to the properties of silica-water interfaces.

We show that the van der Waals–like phase-separation instability of a driven granular gas at zero gravity, previously investigated in two-dimensional settings, persists in three dimensions. We consider a monodisperse granular gas driven by a thermal wall of a three-dimensional rectangular container at zero gravity. The basic steady state of this system, as described by granular hydrodynamic equations, involves a denser and colder layer of granulate located at the wall opposite to the driving wall. When the inelastic energy loss is sufficiently high, the driven granular gas exhibits, in some range of average densities, negative compressibility in the directions parallel to the driving wall. When the lateral dimensions of the container are sufficiently large, the negative compressibility causes spontaneous symmetry breaking of the basic steady state and a phase separation instability. Event-driven molecular dynamics simulations confirm and complement our theoretical predictions.

We show how discretization affects two major characteristics in complex networks: internode distances (measured as the shortest number of edges between network sites) and average path length, and as a result there are log-periodic oscillations of the above quantities. The effect occurs both in numerical network models as well as in such real systems as coauthorship, language, food, and public transport networks. Analytical description of these oscillations fits well numerical simulations. We consider a simple case of the network optimization problem, arguing that discrete effects can lead to a nontrivial solution.

This paper examines how diseases on random networks spread in time. The disease is described by a probability distribution function for the number of infected and recovered individuals, and the probability distribution is described by a generating function. The time development of the disease is obtained by iterating the generating function. In cases where the disease can expand to an epidemic, the probability distribution function is the sum of two parts; one that is static at long times, and another whose mean grows exponentially. The time development of the mean number of infected individuals is obtained analytically. When epidemics occur, the probability distributions are very broad, and the uncertainty in the number of infected individuals at any given time is typically larger than the mean number of infected individuals.

We investigate a two-level system in resonant contact with a larger environment. The environment typically is in a canonical state with a given temperature initially. Depending on the precise spectral structure of the environment and the type of coupling between both systems, the smaller part may relax to a canonical state with the same temperature as the environment (i.e., thermal relaxation) or to some other quasiequilibrium state (nonthermal relaxation). The type of (quasi)equilibrium state can be related to the distribution of certain properties of the energy eigenvectors of the total system. We examine these distributions for several abstract and concrete (spin environment) Hamiltonian systems; the significant aspect of these distributions can be related to the relative strength of the local and interaction parts of the Hamiltonian.

A multiscale model for the diagenesis of carbonate rocks is proposed. It captures important pore scale characteristics of carbonate rocks: wide range of length scales in the pore diameters; large variability in the permeability; and strong dependence of the geometrical and transport parameters on the resolution. A pore scale microstructure of an oolithic dolostone with generic diagenetic features is successfully generated. The continuum representation of a reconstructed cubic sample of sidelength $2\mathrm{mm}$ contains roughly $42\times {10}^6$ crystallites and pore diameters varying over many decades. Petrophysical parameters are computed on discretized samples of sizes up to ${1000}^3$. The model can be easily adapted to represent the multiscale microstructure of a wide variety of carbonate rocks.

We discuss how a system of particles with bounded interaction potentials responds to increased densities. In particular we elaborate the ability of a system to form potential barriers between the particles, to allow a so called cluster formation. These theoretical considerations are complemented by computer simulations that allow us to observe the onset of clustering at low particle densities. We discuss the simulation results with regard to the presence of potential barriers and establish a formulation to explain the effect of potential barriers by the use of the Fourier transform of the potential function.

Our experimental study investigates the interaction of pairs of nearly spherical solid particles suspended in a stratified shear flow inside a Couette cell. The surfaces of the particles are well characterized, with roughness maps produced by a scanning electron microscope. We measure the degree of irreversibility introduced into the flow by particle interactions and relate it to the subtle differences in the particle surface features.

We study the critical properties of the majority voter model by using two different transition rates: the Glauber rate and the Metropolis rate. The model with the Glauber rate has been found to be mapped to the majority voter model with noise [de Oliveira, J. Stat. Phys. 66, 273 (1992)]. The critical temperature and the critical exponents for the two transition rates are obtained from a Monte Carlo simulation with a finite size scaling analysis. The critical temperature is found to depend on the transition rate, but the critical exponents do not. The values of the critical exponents obtained indicate that the model belongs to the same universality class as the Ising model, regardless of the type of transition rate.

We report results from molecular dynamics studies concerning the microscopic structure and dynamics of the ternary, bulk metallic glass-forming ${\mathrm{Cu}}_{60}{\mathrm{Ti}}_{20}{\mathrm{Zr}}_{20}$ alloy. In detail we consider the partial radial distribution functions, nearest-neighbor numbers, specific heat, simulated glass temperature, diffusion coefficients, and incoherent intermediate scattering function (ISF). The applied atomic model reproduces well experimental x-ray data of the total radial distribution function. It provides for ${\mathrm{Cu}}_{60}{\mathrm{Ti}}_{20}{\mathrm{Zr}}_{20}$ a structure with marked intermediate-range order. The ISF is analyzed within an extension of mode-coupling theory, where the effective memory kernel is evaluated from the Laplace transform of the ISF. The dynamics of the system fulfills in most respects the predictions of mode-coupling theory (MCT), up to an absence of the algebraic $t^{-a}$ decay in the early $\beta$ range. Comparison with the calculated memory kernel shows that this absence can be traced back to deviations of the kernel from its approximate form analyzed in MCT. As by-product, our investigation provides a method to reconstruct around the critical temperature major parts of the memory kernel from $\lambda$ and the plateau value $f^c$ of the ISF, and it indicates why the critical dynamics predicted by mode-coupling theory can be observed in a temperature interval of more than $500\mathrm{K}$.

Even if photochemical deposition of nearly all types of materials has been used for decades to pattern almost any kind of substrate for various applications (catalysis, chemical sensing, magnetic data storage, optoelectronics, spin-dependent electron transport, and solar cells), a rationalized description is still missing. This paper aims at fulfilling this lack by presenting a unified approach of the photodeposit growth initiated by a one-photon photochemical reaction. We experimentally investigate the robustness of growth scalings predicted for photochemical deposition driven by a continuous laser wave. Three types of one-photon photochemical reactions (photoexcitation of chromates, photodissociation of permanganates, and photocondensation of colloidal selenium) and three parameters (solvent $p$H variations, concentration in photoactive reagent, and influence of the exciting optical wavelength) were cross analyzed. In all the cases, including data taken from the literature, the same dynamic master behavior emerges from the data rescaling of measured deposit growth laws. The nice agreement observed between system-independent predictions and the whole data set strongly supports a universal description of the photodeposit growth whatever the photosensitive medium and the involved one-photon chemical reaction. Such an approach also points out the quantitative sorting of photochemical reactions in terms of deposition efficiency. This rationalization of the kinetics of photodeposition anticipates new methodologies to predict, design, and control substrate micropatterning for chemical, lithographic, and optoelectronic applications.

We present a general thermodynamic picture of the folding of RNA-like heteropolymer based on the basic physical principles. The Hamiltonian of the model includes all characteristic interactions explicitly. A particular attention is paid to the electrostatic interactions whose role in the RNA folding is known to be crucial. In this paper we study RNA folding with the full Hamiltonian and describe the spin-glass behavior on the level of tertiary structure. We show that formation of the stable tertiary structure is possible in the random RNA-like molecule. By including into the model the nonspecific interactions of the RNA molecule with counterions, we derive the logarithmic dependencies of the melting and freezing temperatures on the ion concentration, which is consistent with experimental data [R. Shiman and D. E. Draper, J. Mol. Biol. 302, 79 (2000)]. We also infer that the large RNA folds slower than the hierarchical model predicts, which was observed in the experiments.

We report on new instabilities of the quasistatic equilibrium of water drops pinned by a hydrophobic inclined substrate. The contact line of a statically pinned drop exhibits three transitions of partial depinning: depinning of the advancing and receding parts of the contact line and depinning of the entire contact line leading to the drop’s translational motion. We find a region of parameters where the classical Macdougall-Ockrent-Frenkel approach fails to estimate the critical volume of the statically pinned inclined drop.

A reaction-diffusion master equation has been introduced in order to model the bistable $\mathrm{CO}$ oxidation on single crystal metal surfaces at high pressure where the diffusion length becomes small and local fluctuations are important. Analytical solutions can be found in a reduced one-component nonlinear master equation after applying the Weiss mean-field approximation together with the adiabatic elimination of oxygen. It is shown that the Weiss mean-field approximation predicts a symmetry-breaking bifurcation associated with a phase transition. The corresponding stationary solutions of the nonlinear master equation are supported by Gillespie-type Monte Carlo simulations.

Using the Wang-Landau sampling method with a two-dimensional random walk we determine the density of states for an asymmetric Ising model with two- and three-body interactions on a triangular lattice, in the presence of an external field. With an accurate density of states we were able to map out the phase diagram accurately and perform quantitative finite-size analyses at, and away from, the critical endpoint. We observe a clear divergence of the curvature of the spectator phase boundary and of the magnetization coexistence diameter derivative at the critical endpoint, and the exponents for both divergences agree well with previous theoretical predictions.