M Khoury

University of Barcelona, Barcino, Catalonia, Spain

Are you M Khoury?

Claim your profile

Publications (5)13.64 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Communicated by Igor Goychuk Particles driven through a periodic potential by an external constant force are known to exhibit a pronounced peak of the diffusion around the critical deterministic force that defines the transition between locked and running states. It has recently been shown both experimentally and numerically that this peak is greatly enhanced if some amount of spatial disorder is superimposed on the periodic potential. Here, we show that this enhancement is a fingerprint of a broad phenomenology that goes well beyond a sim-ple augmentation. For some values of the model parameters, including the characteristic distances associated with the periodic and random components of the potential, the mag-nitude of the external force, and the temperature, the system can exhibit a rich variety of regimes from normal diffusion to superdiffusion, subdiffusion and even subtransport.
    Fluctuation and Noise Letters 03/2012; 11(01). DOI:10.1142/S0219477512400044 · 0.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Particles driven through a periodic potential by an external constant force are known to exhibit a pronounced peak of the diffusion around a critical force that defines the transition between locked and running states. It has recently been shown both experimentally and numerically that this peak is greatly enhanced if some amount of spatial disorder is superimposed on the periodic potential. Here we show that beyond a simple enhancement lies a much more interesting phenomenology. For some parameter regimes the system exhibits a rich variety of behaviors from normal diffusion to superdiffusion, subdiffusion and even subtransport.
    Physical Review Letters 03/2011; 106(9):090602. DOI:10.1103/PhysRevLett.106.090602 · 7.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Transport and diffusion of particles on modulated surfaces is a nonequilibrium problem which is receiving a great deal of attention due to its technological applications, but analytical calculations are scarce. In earlier work, we developed a perturbative approach to begin to provide an analytic platform for predictions about particle trajectories over such surfaces. In some temperature and forcing regimes, we successfully reproduced results for average particle velocities obtained from numerical simulations. In this paper, we extend the perturbation theory to the calculation of higher moments, in particular the diffusion tensor and the skewness. Numerical simulations are used to check the domain of validity of the perturbative approach.
    Physical Review E 08/2009; 80(2 Pt 1):021123. DOI:10.1103/PhysRevE.80.021123 · 2.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Sorting of colloidal particles of different sizes is of importance in the transport and delivery of such particles in biological, materials science, and other technological contexts. A successful methodology involves the flow of a mixture of particles over designer surfaces presenting a periodic array of traps (optical tweezers) or microfabricated obstacles. The trajectories of the particles over these surfaces deviate from the direction of flow as the particles are attracted (traps) or repelled (obstacles) by the features of the landscape. The deviation of the particles from that of the flow depends on particle size (or on some other particle characteristic) and hence the particles can be sorted according to trajectory direction. On the basis of extensive numerical simulations, we present a unified view of these methodologies and discuss the effects of system parameters such as the magnitude and direction of the flow on the sorting efficacy.
    Modern Physics Letters B 10/2006; 20(23):1427-1442. DOI:10.1142/S0217984906011979 · 0.69 Impact Factor
  • Source
    J M Sancho · M Khoury · K Lindenberg · A M Lacasta
    [Show abstract] [Hide abstract]
    ABSTRACT: 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 with periodic traps or periodic obstacles driven by a constant external force, and present new results for particles moving in a harmonic periodic potential. The sorting properties are explored as a function of a number of control parameters, specifically the friction, force amplitude and direction, temperature, and lattice constants.
    Journal of Physics Condensed Matter 12/2005; 17:4151-4163. DOI:10.1088/0953-8984/17/49/010 · 2.35 Impact Factor

Publication Stats

70 Citations
13.64 Total Impact Points

Institutions

  • 2005–2012
    • University of Barcelona
      • Department of Structure and Constituents of Matter
      Barcino, Catalonia, Spain
  • 2011
    • Instituto de Estructura de la Materia
      Madrid, Madrid, Spain