The multi-agent Parrondo’s model based on the network evolution

A multi-agent Parrondo’s model is proposed in the paper. The model includes link A based on the rewiring mechanism (the network evolution) + game B (dependent on the spatial neighbors). Moreover, to produce the paradoxical effect and analyze the “agitating” effect of the network evolution, the dynamic processes of the network evolution + game B are studied. The simulation results and the theoretical analysis both show that the network evolution can make game B which is losing produce the winning paradoxical effect. Furthermore, we obtain the parameter space where the strong or weak Parrondo’s paradox occurs. Each size of the region of the parameter space is larger than the one in the available multi-agent Parrondo’s model of game A + game B. This result shows that the “agitating” effect of rewiring based on the network evolution is better than that of the zero-sum game between individuals.     

Combinatorial approach to the fabrication of organic thin films

We demonstrate combinatorial approach in investigation of organic thin film fabrication. “Combinatorial substrate screening”, which is the deposition onto several kinds of substrates simultaneously, is useful to choose suitable substrate for organic thin film growth. “Combinatorial thickness-gradient films” can be fabricated using a moving mask which travels from an edge to another edge of substrate continuously during the deposition. The combinatorial thickness-gradient film can be regarded as the library for time evolution of film growth during the deposition. This mapping can serve as a powerful method for the research of growth of thin film in an initial stage. Besides, combinatorial thickness-gradient film can be utilized for the examination of a buffer layer effect. These techniques enable us to quickly optimize for the fabrication of high-quality organic thin films.     

A four-level “Ξ-system”: Exact solvability and effective evolution operators via multiple scales

Properties of a four-level atomic system interacting with one and two modes of the electromagneticfield in a “Ξ”-configuration are investigated. By linearization of the Hamiltonians we show that the corresponding mathematical models are exactly solvable. To obtain simpler effective Hamiltonians the perturbative method of multiple scales is applied. The lowest-order corrections to the resulting effective evolution operators are also calculated.     

Formation mechanism of “memory” phenomenon of microchannel plate image intensifier

A discrete resistance capacitance dynodes chain of channel multiplication model worked in a continuous variable dynode number described here is an attempt to explain the formation mechanism of “memory” phenomenon of microchannel plate image intensifier, wherein it was concluded conclusion that “memory” phenomenon of image intensifiers were the results of a silicon-rich layer, which existed between emission layer and conduction layer of channel inner wall of microchannel plate, having much higher resistance as compared with the conduction layer, and there are two distinct appearance ways of “negative memory” and “positive memory” only due to a difference in illumination and duration of the image intensifier suffered, and a strictly controlled MCP manufacture process would make considerable reduction of “memory” phenomenon occurrence ratio.     

Effects of metal and “magnetic wall” on the dispersion characteristic of magnetostatic waves

The dispersion relation of magnetostatic waves tangentially magnetized to saturation ferrite film, with a “magnetic wall” condition (tangential component of microwave magnetic field is equal to zero) on one of the film surface and with a metal condition on the opposite surface is analyzed. The dispersion characteristics show that unidirectional magnetostatic waves appear in this structure: they can transfer energy in one direction only and fundamentally cannot transfer energy in the opposite direction. The dispersion-free propagation of magnetostatic waves also is possible in the structure in a wide frequency interval.     

Understanding the time dependence of atomic level populations in evolving plasmas

The time dependence of atomic level populations in evolving plasmas is studied using an eigenfunction expansion of the non-LTE rate equations. The work aims to develop understanding without the need for, and as an aid to, numerical solutions. The discussion is mostly limited to linear systems, especially those for optically thin plasmas, but the implicitly non-linear case of non-LTE radiative transfer is briefly discussed. Eigenvalue spectra for typical atomic systems are examined using results compiled by Hearon. Diagonal dominance and sign symmetry of rate matrices show that just one eigenvalue is zero (corresponding to the equilibrium state), that the remaining eigenvalues have negative real parts, and that oscillations, if any, are necessarily damped. Gershgorin's theorems are used to show that many eigenvalues are determined by the radiative lifetimes of certain levels, because of diagonal dominance. With other properties, this demonstrates the existence of both “slow” and “fast” time-scales, where the “slow” evolution is controlled by properties of meta-stable levels. It is shown that, when collisions are present, Rydberg states contribute only “fast” eigenvalues. This justifies use of the quasi-static approximation, in which atoms containing just meta-stable levels can suffice to determine the atomic evolution on time-scales long compared with typical radiative lifetimes. Analytic solutions for two- and three-level atoms are used to examine the basis of earlier intuitive ideas, such as the “ionizing plasma” approximation. The power and limitations of Gershgorin's theorems are examined through examples taken from the solar atmosphere. The methods should help in the planning and interpretation of both experimental and numerical experiments in which atomic evolution is important. While the examples are astrophysical, the methods and results are applicable to plasmas in general.     

Statistical dynamics of religion evolutions

A religion affiliation can be considered as a “degree of freedom” of an agent on the human genre network. A brief review is given on the state of the art in data analysis and modelization of religious “questions” in order to suggest and if possible initiate further research, after using a “statistical physics filter”. We present a discussion of the evolution of 18 so-called religions, as measured through their number of adherents between 1900 and 2000. Some emphasis is made on a few cases presenting a minimum or a maximum in the investigated time range—thereby suggesting a competitive ingredient to be considered, besides the well accepted “at birth” attachment effect. The importance of the “external field” is still stressed through an Avrami late stage crystal growth-like parameter. The observed features and some intuitive interpretations point to opinion based models with vector, rather than scalar, like agents.     

Dynamics of surface reactions: from “hot” precursors to conventional thermal activation

Heterogeneous catalytic reactions usually contain steps, e.g., adsorption, generating energy-rich (“hot”) precursors for other steps. With increasing the rate of energy relaxation one can observe a transition from the reaction regime dominated by “hot” precursors to conventional thermal activation. To illustrate this transition in detail and to show what may happen in various situations, I present an analytical model based on the Fokker-Planck equation for energy relaxation.     

A comment on the paper “Stochastic feedback, nonlinear families of Markov processes, and nonlinear Fokker-Planck equations” by T.D. Frank

The purpose of this comment is to correct mistaken assumptions and claims made in the paper “Stochastic feedback, nonlinear families of Markov processes, and nonlinear Fokker-Planck equations” by T. D. Frank [T.D. Frank, Stochastic feedback, non-linear families of Markov processes, and nonlinear Fokker-Planck equations, Physica A 331 (2004) 391]. Our comment centers on the claims of a “non-linear Markov process” and a “non-linear Fokker-Planck equation.” First, memory in transition densities is misidentified as a Markov process. Second, the paper assumes that one can derive a Fokker-Planck equation from a Chapman-Kolmogorov equation, but no proof was offered that a Chapman-Kolmogorov equation exists for the memory-dependent processes considered. A “non-linear Markov process” is claimed on the basis of a non-linear diffusion pde for a 1-point probability density. We show that, regardless of which initial value problem one may solve for the 1-point density, the resulting stochastic process, defined necessarily by the conditional probabilities (the transition probabilities), is either an ordinary linearly generated Markovian one, or else is a linearly generated non-Markovian process with memory. We provide explicit examples of diffusion coefficients that reflect both the Markovian and the memory-dependent cases. So there is neither a “non-linear Markov process”, nor a “non-linear Fokker-Planck equation” for a conditional probability density. The confusion rampant in the literature arises in part from labeling a non-linear diffusion equation for a 1-point probability density as “non-linear Fokker-Planck,” whereas neither a 1-point density nor an equation of motion for a 1-point density can define a stochastic process. In a closely related context, we point out that Borland misidentified a translation invariant 1-point probability density derived from a non-linear diffusion equation as a conditional probability density. Finally, in the Appendix A we present the theory of Fokker-Planck pdes and Chapman-Kolmogorov equations for stochastic processes with finite memory.     

Microstructural evolution of tungsten oxide thin films

Tungsten oxide thin films are of great interest due to their promising applications in various optoelectronic thin film devices. We have investigated the microstructural evolution of tungsten oxide thin films grown by DC magnetron sputtering on silicon substrate. The structural characterization and surface morphology were carried out using X-ray diffraction and Scanning Electron Microscopy (SEM). The as deposited films were amorphous, where as, the films annealed above 400 °C were crystalline. In order to explain the microstructural changes due to annealing, we have proposed a “instability wheel” model for the evolution of the microstructure. This model explains the transformation of mater into various geometries within them selves, followed by external perturbation.     

Chemical modification of silica-gel with diethylenetriamine via an end-group protection approach for adsorption to Hg(II)

Four kinds of silica-gel supported diethylenetriamine adsorbents with different structures, were prepared by so-called “heterogeneous-direct-amination” (hetero-DA), “homogeneous-direct-amination” (homo-DA), “heterogeneous end-group protection” (hetero-EGP), and “homogeneous end-group protection” (homo-EGP) methods, respectively. The obtained products were named SG-HE-dD, SG-HO-dD, SG-HE-pD and SG-HO-pD, respectively (where SG means silica-gel; HE means heterogeneous, HO means homogeneous, d means direct, p means protected and D means diethylenetriamine). Their structures were characterized by FT-IR, elemental analysis, porous structure analysis and thermogravimetric analysis. The adsorption capabilities of such adsorbents towards Hg(II) were studied and evaluated by static method. SG-HE-pD and SG-HO-pD showed higher performance towards Hg(II) adsorption than corresponding counterparts SG-HE-dD and SG-HO-dD, even though the former two possessed lower contents of diethylenetriamine (DETA). The kinetics data indicated that the adsorption process was governed by the film diffusion and followed pseudo-first-order rate model for SG-HE-dD, SG-HO-dD and SG-HE-pD and pseudo-second-order model for SG-HO-pD. The Langmuir model was applied to fit the experimental equilibrium data for all adsorbents. The end-group protection method exhibited its advantage in preparation of effective adsorbent for metal ions uptake compared to the direct-amination method.     

Surface modifications induced by the friction of graphites against steel

Graphite is a well-known, multipurpose material used in many applications including tribology, electrochemistry and metallurgy. In this study, we focused our attention on the modifications of the surfaces of graphite pins, one natural and two synthetic, in dynamic contact against steel. Specifically, we explored the effect of the normal load applied to the contact, on the friction behaviour of graphites.The results of the series of tests under “low” loads indicated that the friction coefficient and the transfer film forming tendency increased with increasing load, due to the modification of the morphology of the contact area. Whereas experiments under “high” loads revealed the existence of a critical load at which a sudden decrease of both the coefficient of friction and the transfer film forming tendency is observed. The reorientation of the graphitic planes is supposed to be at the origin of this phenomenon.     

Comment on “Time-changed geometric fractional Brownian motion and option pricing with transaction costs” by Hui Gu et al.

The purpose of this comment is to point out the inappropriate assumption of “3αH>1$3\alpha H>1$” and two problems in the proof of “Theorem 3.1” in section 3 of the paper “Time-changed geometric fractional Brownian motion and option pricing with transaction costs” by Hui Gu et al. [H. Gu, J.R. Liang, Y. X. Zhang, Time-changed geometric fractional Brownian motion and option pricing with transaction costs, Physica A 391 (2012) 3971–3977]. Then we show the two problems will be solved under our new assumption.     

A last updating evolution model for online social networks

As information technology has advanced, people are turning to electronic media more frequently for communication, and social relationships are increasingly found on online channels. However, there is very limited knowledge about the actual evolution of the online social networks. In this paper, we propose and study a novel evolution network model with the new concept of “last updating time”, which exists in many real-life online social networks. The last updating evolution network model can maintain the robustness of scale-free networks and can improve the network reliance against intentional attacks. What is more, we also found that it has the “small-world effect”, which is the inherent property of most social networks. Simulation experiment based on this model show that the results and the real-life data are consistent, which means that our model is valid.     

Classicalization times of parametrically amplified “Schrödinger cat” states coupled to phase-sensitive reservoirs

The exact Wigner function of a parametrically excited quantum oscillator in a phase-sensitive amplifying/attenuating reservoir is found for initial even/odd coherent states. Studying the evolution of negativity of the Wigner function we show the difference between the “initial positivization time” (IPT), which is inversely proportional to the square of the initial size of the superposition, and the “final positivization time” (FPT), which does not depend on this size. Both these times can be made arbitrarily long in maximally squeezed high-temperature reservoirs. Besides, we find the conditions when some (small) squeezing can exist even after the Wigner function becomes totally positive.     

Between complexity of modelling and modelling of complexity: An essay on econophysics

Econophysics is an emerging field dealing with complex systems and emergent properties. A deeper analysis of themes studied by econophysicists shows that research conducted in this field can be decomposed into two different computational approaches: “statistical econophysics” and “agent-based econophysics”. This methodological scission complicates the definition of the complexity used in econophysics. Therefore, this article aims to clarify what kind of emergences and complexities we can find in econophysics in order to better understand, on one hand, the current scientific modes of reasoning this new field provides; and on the other hand, the future methodological evolution of the field.     

Number-phase entropic uncertainty relations and Wigner functions for solvable quantum systems with discrete spectra

In this Letter, the “number-phase entropic uncertainty relation” and the “number-phase Wigner function” of generalized coherent states associated to a few solvable quantum systems with non-degenerate spectra are studied. We also investigate time evolution of “number-phase entropic uncertainty” and “Wigner function” of the considered physical systems with the help of temporally stable Gazeau-Klauder coherent states.     

Modeling “unilateral” response in the cross-ties of a cable network: Deterministic vibration

Cross-ties are employed as passive devices for the mitigation of stay-cable vibrations, exhibited on cable-stayed bridges under wind and wind-rain excitation. Large-amplitude oscillation can result in damage to the cables or perceived discomfort to bridge users. The “cable-cross-ties system” derived by connecting two or more stays by transverse cross-ties is often referred to as an “in-plane cable network”. Linear modeling of network dynamics has been available for some time. This framework, however, cannot be used to detect incipient failure in the restrainers due to slackening or snapping. A new model is proposed in this paper to analyze the effects of a complete loss in the pre-tensioning force imparted to the cross-ties, which leads to the “unilateral” free-vibration response of the network (i.e., a cross-tie with linear-elastic internal force in tension and partially inactive in compression).     

A case of subdominant/suppressed “high energy” contribution to the baryon asymmetry of the Universe in flavoured leptogenesis

The CP-violation necessary for the generation of the baryon asymmetry of the Universe YB$Y_B$ in the “flavoured” leptogenesis scenario can arise from the “low energy” PMNS neutrino mixing matrix U   and/or from the “high energy” part of neutrino Yukawa couplings, which can mediate CP-violating phenomena only at some high energy scale. The possible interplay between these two types of CP-violation is analysed. The type I see-saw model with three heavy right-handed Majorana neutrinos having hierarchical spectrum is considered. We show that in the case of inverted hierarchical light neutrino mass spectrum, there exist regions in the corresponding leptogenesis parameter space where the relevant “high energy” phases have large CP-violating values, but the purely “high energy” contribution in YB$Y_B$ plays a subdominant role in the production of baryon asymmetry compatible with the observations. In some of these regions the purely “high energy” contribution in YB$Y_B$ is so strongly suppressed that one can have successful leptogenesis only if the requisite CP-violation is provided by the Majorana phase(s) in the neutrino mixing matrix.