Search results for "Linear"
showing 10 items of 7165 documents
Generation of Entangled Two-Photon Binomial States in Two Spatially Separate Cavities
2006
We propose a conditional scheme to generate entangled two-photon generalized binomial states inside two separate single-mode high-Q cavities. This scheme requires that the two cavities are initially prepared in entangled one-photon generalized binomial states and exploits the passage of two appropriately prepared two-level atoms one in each cavity. The measurement of the ground state of both atoms is finally required when they exit the cavities. We also give a brief evaluation of the experimental feasibility of the scheme.
Stochastic model for the epitaxial growth of two-dimensional islands in the submonolayer regime
2016
The diffusion-based growth of islands composed of clusters of metal atoms on a substrate is considered in the aggregation regime. A stochastic approach is proposed to describe the dynamics of island growth based on a Langevin equation with multiplicative noise. The distribution of island sizes, obtained as a solution of the corresponding Fokker-Planck equation, is derived. The time-dependence of island growth on its fractal dimension is analysed. The effect of mobility of the small islands on the growth of large islands is considered. Numerical simulations are in a good agreement with theoretical results.
Experimental investigations of local stochastic resistive switching in yttria stabilized zirconia film on a conductive substrate
2020
We report on the results of the experimental investigations of the local resistive switching (RS) in the contact of a conductive atomic force microscope (CAFM) probe to a nanometer-thick yttria stabilized zirconia (YSZ) film on a conductive substrate under a Gaussian noise voltage applied between the probe and the substrate. The virtual memristor was found to switch randomly between the low resistance state and the high resistance state as a random telegraph signal (RTS). The potential profile of the virtual memristor calculated from its response to the Gaussian white noise shows two local minima, which is peculiar of a bistable nonlinear system.
Polydisperse hard spheres: crystallization kinetics in small systems and role of local structure
2016
We study numerically the crystallization of a hard-sphere mixture with 8\% polydispersity. Although often used as a model glass former, for small system sizes we observe crystallization in molecular dynamics simulations. This opens the possibility to study the competition between crystallization and structural relaxation of the melt, which typically is out of reach due to the disparate timescales. We quantify the dependence of relaxation and crystallization times on density and system size. For one density and system size we perform a detailed committor analysis to investigate the suitability of local structures as order parameters to describe the crystallization process. We find that local…
To make a glass—avoid the crystal
2016
Colloidal model systems allow for a flexible tuning of particle sizes, particle spacings and mutual interactions at constant temperature. Colloidal suspensions typically crystallize as soon as the interactions get sufficiently strong and long-ranged. Several strategies have been successfully applied to avoid crystallization and instead produce colloidal glasses. Most of these amorphous solids are formed at high particle concentrations. This paper shortly reviews experimental attempts to produce amorphous colloidal solids using strategies based on topological, thermodynamic and kinetic considerations. We complement this overview by introducing a (transient) amorphous solid forming in a thoro…
Relaxation of Electron Spin during High-Field Transport in GaAs Bulk
2011
A semiclassical Monte Carlo approach is adopted to study the multivalley spin depolarization of drifting electrons in a doped n-type GaAs bulk semiconductor, in a wide range of lattice temperature ($40<T_L<300$ K) and doping density ($10^{13}<n<10^{16}$cm$^{-3}$). The decay of the initial non-equilibrium spin polarization of the conduction electrons is investigated as a function of the amplitude of the driving static electric field, ranging between 0.1 and 6 kV/cm, by considering the spin dynamics of electrons in both the $\Gamma$ and the upper valleys of the semiconductor. Doping density considerably affects spin relaxation at low temperature and weak intensity of the driving electric fiel…
Quantitative analysis of numerical estimates for the permeability of porous media from lattice-Boltzmann simulations
2010
During the last decade, lattice-Boltzmann (LB) simulations have been improved to become an efficient tool for determining the permeability of porous media samples. However, well known improvements of the original algorithm are often not implemented. These include for example multirelaxation time schemes or improved boundary conditions, as well as different possibilities to impose a pressure gradient. This paper shows that a significant difference of the calculated permeabilities can be found unless one uses a carefully selected setup. We present a detailed discussion of possible simulation setups and quantitative studies of the influence of simulation parameters. We illustrate our results b…
Noise-induced resistive switching in a memristor based on ZrO2(Y)/Ta2O5 stack
2019
Resistive switching (RS) is studied in a memristor based on a ZrO2(Y)/Ta2O5 stack under a white Gaussian noise voltage signal. We have found that the memristor switches between the low resistance state and the high resistance state in a random telegraphic signal (RTS) mode. The effective potential profile of the memristor shows from two to three local minima and depends on the input noise parameters and the memristor operation. These observations indicate the multiplicative character of the noise on the dynamical behavior of the memristor, that is the noise perceived by the memristor depends on the state of the system and its electrical properties are influenced by the noise signal. The det…
Dynamics of a map with a power-law tail
2008
We analyze a one-dimensional piecewise continuous discrete model proposed originally in studies on population ecology. The map is composed of a linear part and a power-law decreasing piece, and has three parameters. The system presents both regular and chaotic behavior. We study numerically and, in part, analytically different bifurcation structures. Particularly interesting is the description of the abrupt transition order-to-chaos mediated by an attractor made of an infinite number of limit cycles with only a finite number of different periods. It is shown that the power-law piece in the map is at the origin of this type of bifurcation. The system exhibits interior crises and crisis-induc…
Lyapunov exponent and topological entropy plateaus in piecewise linear maps
2013
We consider a two-parameter family of piecewise linear maps in which the moduli of the two slopes take different values. We provide numerical evidence of the existence of some parameter regions in which the Lyapunov exponent and the topological entropy remain constant. Analytical proof of this phenomenon is also given for certain cases. Surprisingly however, the systems with that property are not conjugate as we prove by using kneading theory.