Now showing items 16-35 of 47

  • External fluctuations in front propagation 

    Armero Rovira, J.; Sancho, Jose Maria; Casademunt, Jaume; Lacasta Palacio, Ana María; Ramírez de la Piscina Millán, Laureano; Sagués Mestre, Francesc (American Physical Society, 1996-04-01)
    Article
    Open Access
    We study the effects of external noise in a one-dimensional model of front propagation. Noise is introduced through the fluctuations of a control parameter leading to a multiplicative stochastic partial differential equation. ...
  • First-passage time in a bistable potential with colored noise 

    Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria; de la Rubia, Francisco Javier; Lindenberg, Katja; Tsironis, G P (1989-08-15)
    Article
    Open Access
    A precise digital simulation of a bistable system under the effect of colored noise is carried out. A set of data for the mean first-passage time is obtained. The results are interpreted and compared with presently available ...
  • First-passage times for a marginal state driven by colored noise 

    Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria (The American Physical Society, 1991-01-18)
    Article
    Open Access
    The dynamical process through a marginal state (saddle point) driven by colored noise is studied. For small correlation time of the noise, the mean first-passage time and its variance are calculated using standard methods. ...
  • Fluctuations in domain growth: Ginzburg-Landau equations with multiplicative noise 

    Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria; Hernández Machado, Aurora (The American Physical Society, 1993-07-01)
    Article
    Open Access
    Ginzburg-Landau equations with multiplicative noise are considered, to study the effects of fluctuations in domain growth. The equations are derived from a coarse-grained methodology and expressions for the resulting ...
  • From subdiffusion to superdiffusion of particles on solid surfaces 

    Lacasta Palacio, Ana María; Sancho, Jose Maria; Sokolov, Igor M.; Lindenberg, K. (American Physical Society, 2004-11-15)
    Article
    Open Access
    We present a numerical and partially analytical study of classical particles obeying a Langevin equation that describes diffusion on a surface modeled by a two dimensional potential. The potential may be either periodic ...
  • Front and domain growth in the presence of gravity. 

    Lacasta Palacio, Ana María; Hernández-Machado, Aurora; Sancho, Jose Maria (American Physical Society, 1993-10-01)
    Article
    Open Access
    Front and domain growth of a binary mixture in the presence of a gravitational field is studied. The interplay of bulk (and surface) diffusion mechanisms is analyzed. An equation for the evolution of interfaces is derived ...
  • Front propagation in spatially modulated media 

    Armero, J.; Lacasta Palacio, Ana María; Ramírez de la Piscina Millán, Laureano; Casademunt, Jaume; Sancho, Jose Maria; Sagués Mestre, Francesc (American Physical Society, 1997-09-01)
    Article
    Open Access
    A two-dimensional reaction-diffusion front which propagates in a modulated medium is studied. The modulation consists of a spatial variation of the local front velocity in the transverse direction to that of the ...
  • Generation of spatiotemporal colored noise 

    García Ojalvo, Jordi; Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria (American Physical Society, 1992-10-01)
    Article
    Open Access
    We develop an algorithm to simulate a Gaussian stochastic process that is non-δ-correlated in both space and time coordinates. The colored noise obeys a linear reaction-diffusion Langevin equation with Gaussian white noise. ...
  • Higher order colored noise effects in multivariable systems. 

    Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria (American Physical Society, 1988-06-01)
    Article
    Open Access
    We extend the partial resummation technique of Fokker-Planck terms for multivariable stochastic differential equations with colored noise. As an example, a model system of a Brownian particle with colored noise is studied. ...
  • Implementación de los métodos de Riks-Wempner, Batoz-Dhatt, Powell-Simons y otros en el programa de elementos finitos F.E.A.P 

    Sancho, Jose Maria; Ortiz, Jesús (2009-03-09T16:16:24Z)
    Article
    Open Access
    Los fundamentos teóricos del método de Riks y su utilidad para el paso de puntos límite en el análisis no lineal de estructuras, están actualmente bien establecidos, pero resta aún una importante labor de normalización y ...
  • Langevin dynamics of A+A reactions in one dimension 

    Sancho, Jose Maria; Romero, A. H.; Lacasta Palacio, Ana María; Lindenberg, Katja (IOP Publishing, 2007-02-28)
    Article
    Open Access
    We propose a set of Langevin equations of motion together with a reaction rule for the study of binary reactions. Our scheme is designed to address this problem for arbitrary friction ° and temperature T. It easily ...
  • Langevin equations with multiplicative noise: application to domain growth 

    Sancho, Jose Maria; Hernández-Machado, A.; Ramírez de la Piscina Millán, Laureano; Lacasta Palacio, Ana María (Jagiellonian University, Polish Academy of Arts and Sciences, 1993-05-01)
    Article
    Open Access
    Langevin Equations of Ginzburg--Landau form, with multiplicative noise, are proposed to study the effects of fluctuations in domain growth. These equations are derived from a coarse-grained methodology. The Cahn--Hiliard--Cook ...
  • Modelization of surface diffusion of a molecular dimer 

    Romero, A. H.; Lacasta Palacio, Ana María; Sancho, Jose Maria (American Physical Society, 2004-05-20)
    Article
    Open Access
    A simple model for a dimer molecular diffusion on a crystalline surface, as a function of temperature, is presented. The dimer is formed by two particles coupled by a quadratic potential. The dimer diffusion is modeled by ...
  • Numerical algorithm for Ginzburg-Landau equations with multiplicative noise: application to domain growth 

    Ramírez de la Piscina Millán, Laureano; Sancho, Jose Maria; Hernández Machado, Aurora (The American Physical Society, 1993-07-01)
    Article
    Open Access
    We consider stochastic partial differential equations with multiplicative noise. We derive an algorithm for the computer simulation of these equations. The algorithm is applied to study domain growth of a model with a ...
  • Numerical study of A+A -> 0 and A+B ->0 reactions with inertia 

    Romero, A. H.; Lacasta Palacio, Ana María; Sancho, Jose Maria; Lindenberg, Katja (American Institute of Physics, 2007-11-30)
    Article
    Open Access
    Using numerical methods we study the annihilation reactions A + A → 0 and A + B → 0 in one and two dimensions in the presence of inertial contributions to the motion of the particles. The particles move freely following ...
  • Particle separation by external fields on periodic surfaces 

    Sancho, Jose Maria; Khoury, M.; Lindenberg, K.; Lacasta Palacio, Ana María (http://dx.doi.org/10.1063/1.478548, 2005-11-30)
    Article
    Open Access
    Particles moving on perfect periodic surfaces under the influence of external forces may move along directions that deviate from that of the force. We briefly recall previous results for transport of particles on surfaces ...
  • Pattern and velocity selection of fronts propagating in modulated media 

    Armero, J.; Lacasta Palacio, Ana María; Ramírez de la Piscina Millán, Laureano; Casademunt, Jaume; Sancho, Jose Maria; Sagués Mestre, Francesc (EDP Sciences, 1996-02-01)
    Article
    Open Access
    We study the problem of pattern and velocity selection of morphologically stable two-dimensional fronts propagating in a spatially modulated medium. The generic system is governed by a local equation and evolves towards a ...
  • Phase separation driven by external fluctuations 

    García Ojalvo, Jordi; Lacasta Palacio, Ana María; Sancho, Jose Maria; Toral, R. (EDP Sciences, 1998-04-30)
    Article
    Open Access
    The influence of external fluctuations in phase separation processes is analysed. These fluctuations arise from random variations of an external control parameter. A linear stability analysis of the homogeneous state ...
  • Phase separation dynamics in a concetration gradient 

    Lacasta Palacio, Ana María; Sancho, Jose Maria; Yeung, C. (EDP Sciences, 1994-08-01)
    Article
    Open Access
    Phase separation dynamics with an initially nonuniform concentration are studied. Critical and off-critical behavior is observed simultaneously. A mechanism for an expanding phase-separated region is demonstrated and the ...
  • Phase separation dynamics under stirring 

    Lacasta Palacio, Ana María; Sancho, Jose Maria; Sagués Mestre, Francesc (American Physical Society, 1995-08-01)
    Article
    Open Access
    Phase separation dynamics in the presence of externally imposed stirring is stuidied. The stirring is assumed independent of the concentration and it is generated with a well-defined energy spectrum. The domain growth ...