We study the problem of optimizing released heat or dissipated work in stochastic thermodynamics. In the overdamped limit these functionals have singular solutions, previously interpreted as protocol jumps. We show that a regularization, penalizing a properly defined acceleration, changes the jumps ...

[Phys. Rev. E 85, 020103] Published Mon Feb 06, 2012

The breakup of small solid aggregates in homogeneous and isotropic turbulence is studied theoretically and by using direct numerical simulations at high Reynolds number, Re_λ≃400. We show that turbulent fluctuations of the hydrodynamic stress along the aggregate trajectory play a key role in determin...

[Phys. Rev. E 85, 025301] Published Fri Feb 03, 2012

We study theoretically the effect of the variation of the elastic constants on the stability of cholesteric blue phases (BPs). We demonstrate that the stability of BPs is greatly enhanced when the bend elastic constant K₃₃ is smaller, in agreement with recent experimental findings. Larger splay (K₁₁...

[Phys. Rev. E 85, 020701] Published Thu Feb 02, 2012

For one-dimensional nonlinear lattices with momentum conserving interparticle interactions, intensive studies have suggested that the heat conductivity κ diverges with the system size L as κ∼L^α and the value of α is universal. But in the Fermi-Pasta-Ulam-β lattices with nearest-neighbor (NN) and nex...

[Phys. Rev. E 85, 020102] Published Wed Feb 01, 2012

We determined the probability distribution of the combined output power from 25 coupled fiber lasers and show that it agrees well with the Tracy-Widom and Majumdar-Vergassola distributions of the largest eigenvalue of Wishart random matrices with no fitting parameters. This was achieved with 500 000...

[Phys. Rev. E 85, 020101] Published Wed Feb 01, 2012

We study the influence of noise on the spatially localized, temporally regular states (stationary, one frequency, two frequencies) in the regime of anomalous dispersion for the cubic-quintic complex Ginzburg-Landau equation as a function of the bifurcation parameter. We find that noise of a fairly s...

[Phys. Rev. E 85, 015205] Published Tue Jan 31, 2012

We experimentally analyze collective dynamics of a population of 20 electronic Wien-bridge limit-cycle oscillators with a nonlinear phase-shifting unit in the global feedback loop. With an increase in the coupling strength we first observe formation and then destruction of a synchronous cluster, so ...

[Phys. Rev. E 85, 015204] Published Tue Jan 31, 2012

An experimental demonstration of reaction-driven viscous fingering developing when a more viscous solution of a reactant A displaces a less viscous miscible solution of another reactant B is presented. In the absence of reaction, such a displacement of one fluid by another less mobile one is classic...

[Phys. Rev. E 85, 015304] Published Mon Jan 30, 2012

An effective numerical method for testing the hyperbolicity of chaotic dynamics is suggested. The method employs ideas of algorithms for covariant Lyapunov vectors but avoids their explicit computation. The outcome is a distribution of a characteristic value which is bounded within the unit interval...

[Phys. Rev. E 85, 015203] Published Fri Jan 27, 2012

We simulate liquid water between hydrophobic walls, separated by 0.5 nm, to study how the diffusion constant D_∥ parallel to the walls depends on the microscopic structure of water. At low temperature T, water diffusion can be associated with the number of defects in the hydrogen bond network. Howeve...

[Phys. Rev. E 85, 010602] Published Fri Jan 27, 2012

We analyze the rectified motion of a Brownian particle in a confined environment. We show the emergence of strong cooperativity between the inherent rectification of the ratchet mechanism and the entropic bias of the fluctuations caused by spatial confinement. Net particle transport may develop even...

[Phys. Rev. E 85, 010105] Published Fri Jan 20, 2012

We present a numerical study of the evolution of height distributions (HDs) obtained in interface growth models belonging to the Kardar-Parisi-Zhang (KPZ) universality class. The growth is done on an initially flat substrate. The HDs obtained for all investigated models are very well fitted by the t...

[Phys. Rev. E 85, 010601] Published Wed Jan 18, 2012

A method to create impacting jets at the micrometer length scale by means of a collapsing cavitation bubble is presented. A focused shock wave from a lithotripter leads to the nucleation of a cavitation bubble below a hole of 25 μm diameter etched in a silicon plate. The plate is placed at an air-wa...

[Phys. Rev. E 85, 015303] Published Tue Jan 17, 2012

The nonlinear dynamics of magnetic helicity H^M, which is responsible for large-scale magnetic structure formation in electrically conducting turbulent media, is investigated in forced and decaying three-dimensional magnetohydrodynamic turbulence. This is done with the help of high-resolution direct ...

[Phys. Rev. E 85, 015302] Published Tue Jan 17, 2012

We have performed a simulation study of three-dimensional cohesionless granular flows down an inclined chute. We find that the oscillations observed in [ L. E. Silbert Phys. Rev. Lett. 94 098002 (2005)] near the angle of repose are harmonic vibrations of the lowest normal mode. Their frequencies de...

[Phys. Rev. E 85, 010301] Published Tue Jan 17, 2012

A unified optimization criterion for Carnot engines and refrigerators is proposed. It consists of maximizing the product of the heat absorbed by the working system times the efficiency per unit time of the device, either the engine or the refrigerator. This criterion can be applied to both low symme...

[Phys. Rev. E 85, 010104] Published Wed Jan 11, 2012

Nelkin scaling, the scaling of moments of velocity gradients in terms of the Reynolds number, is an alternative way of obtaining inertial-range information. It is shown numerically and theoretically for the Burgers equation that this procedure works already for Reynolds numbers of the order of 100 (...

[Phys. Rev. E 85, 015301] Published Tue Jan 10, 2012

Fading is the time-dependent variation in transmitted signal strength through a complex medium due to interference or temporally evolving multipath scattering. In this paper we use random matrix theory (RMT) to establish a first-principles model for fading, including both universal and nonuniversal ...

[Phys. Rev. E 85, 015202] Published Tue Jan 10, 2012

We examine a lattice model of tumor growth where the survival of tumor cells depends on the supplied nutrients. When such a supply is random, the extinction of tumors belongs to the directed percolation universality class. However, when the supply is correlated with the distribution of tumor cells, ...

[Phys. Rev. E 85, 010901] Published Tue Jan 10, 2012

The evanescent wave field outside an optical resonator is typically strongly directional when the shape deviates even very slightly from being perfectly circular or spherical. In this Rapid Communication we show that the tunneling mechanism underlying escape from such weakly deformed resonators can ...

[Phys. Rev. E 85, 015201] Published Thu Jan 05, 2012

While degree correlations are known to play a crucial role for spreading phenomena in networks, their impact on the propagation speed has hardly been understood. Here we investigate a tunable spreading model on scale-free networks and show that the propagation becomes slow in positively (negatively)...

[Phys. Rev. E 85, 015101] Published Thu Jan 05, 2012

We study the mean turnaround time of a Brownian needle in a narrow planar strip. When the needle is only slightly shorter than the width of the strip, the computation becomes a nonstandard narrow escape problem. We develop a boundary layer method, based on a conformal mapping of cusplike narrow stra...

[Phys. Rev. E 85, 010103] Published Thu Jan 05, 2012

Paying attention to the difference of density of states, Δlng(E)≡lng(E+ΔE)−lng(E), we study the convergence of the Wang-Landau method. We show that this quantity is a good estimator to discuss the errors of convergence and refer to the 1/t algorithm. We also examine the behavior of the first-order t...

[Phys. Rev. E 85, 010102] Published Thu Jan 05, 2012

We consider turbulence within the Gross-Pitaevsky model and look into the creation of a coherent condensate via an inverse cascade originating at small scales. The growth of the condensate leads to a spontaneous breakdown of statistical symmetries of overcondensate fluctuations: First, isotropy is b...

[Phys. Rev. E 85, 010101] Published Tue Jan 03, 2012

The higher-order statistics of magnetic field magnitude fluctuations in the fast quiet solar wind are quantified systematically, scale by scale. We find a single global non-Gaussian scale-free behavior from minutes to over 5 h. This spans the signature of an inertial range of magnetohydrodynamic tur...

[Phys. Rev. E 84, 065401] Published Thu Dec 29, 2011

Crumpled paper has recently emerged as a model for disordered media. Here we use wave propagation to probe aluminum foils crumpled into balls made by hand or into cylinders obtained by confinement in a container. Surprisingly, the raw dispersion relations appear to differ from sample to sample. They...

[Phys. Rev. E 84, 065602] Published Tue Dec 27, 2011

We find a statistical mechanism that can adjust orientations of intracellular filaments to cell geometry in the absence of organizing centers. The effect is based on random and isotropic filament (de-)polymerization dynamics and is independent of filament interactions and explicit regulation. It can...

[Phys. Rev. E 84, 060902] Published Tue Dec 27, 2011

An acoustic vortex in an inviscid fluid and its radiation torque on an axisymmetric absorbing object are analyzed beyond the paraxial approximation to clarify an analogy with an optical vortex. The angular momentum flux density tensor from the conservation of angular momentum is used as an efficient...

[Phys. Rev. E 84, 065601] Published Thu Dec 22, 2011

We present an experimental study of drainage in two-dimensional porous media exhibiting bimodal pore size distributions. The role of the pore size heterogeneity is investigated by measuring separately the desaturation curves of the two pore populations. The displaced wetting fluid remains trapped in...

[Phys. Rev. E 84, 065302] Published Thu Dec 22, 2011

The Wang-Landau method of estimating the density of states g(E) has become a powerful tool in statistical mechanics. Here it is shown that the distribution of random walkers sampled using an estimated density of states can always be used to improve the estimate. Specifically, this can be done withou...

[Phys. Rev. E 84, 065702] Published Tue Dec 20, 2011