[Todos] Fwd: Seminario "Regímenes dinánicos inducidos por confinamiento"

[Luciana Bruno]

Estimados,

Les paso este aviso de seminario que me hicieron llegar.

***********************

Se invita al seminario *"Regímenes dinámicos inducidos por confinamiento"  *,
dictado por el Dr. Paolo Malgaretti,   Max Planck Institute for Intelligent
Systems, Germany

*.Fecha: *  *Miércoles  22/8 ,   15 HS.*
*Lugar*:   Laboratorio de Física (aula  7218), Universidad Nacional de
General Sarmiento, Los Polvorines.
*Contacto*:  flor en campus.ungs.edu.ar

Florencia Carusela


*Area de Física Instituto de Ciencias-UNGSemail: flor en campus.ungs.edu
<flor en campus.ungs.edu>.**ar*




*/***************************************************/Confinement--induced
dynamical regimesDr. Paolo Malgaretti,   Max Planck Institute for
Intelligent Systems, Germany*


Recent studies have shown that the presence of boundaries can strongly
affect the dynamics of physical systems.
For example, negative mobility and fluid recirculation occurs when an
electrolyte is driven in a varying-section channels, rectification occurs
active particles such as molecular motors or active swimmers moving in
inhomogeneous environments and off--diagonal terms in the mobility tensor
appears for binary mixtures of hard sphere confined between corrugated
plates.
Clearly the interplay between the confined systems and the confining walls
is maximized when the typical length scales of the confined system match
with the size of the confining walls.
In this contribution I will discuss the general mechanisms at the basis of
the interplay between the confined system and the confinement. In
particular, by means of a few example I will show how analytical insight
into the possible regimes can be attained.

Firstly, I will discuss how the electrostatic interaction between a tracer
particle and the channel walls affect particle dynamics. In such a
scenario, novel dynamical regimes such as negative mobility and asymmetric
passage times can arise due to the interplay between the electrostatic
interactions and the local entropic drive induced by the varying--section
channel.

Secondly I will show how the insight gained by such studies can be
transferred to the problem of polymer translocation across varying--section
channels.
In particular, I will show that, under suitable approximation, it is
possible to reduce the problem of polymer translocation across
varying--section channels to that of a single point--like particle under an
effective potential that can be derived from the equilibrium local free
energy of the polymer. Interestingly, the model predicts a non-monotonous
dependence on the translocation time of the polymer across the pore
appears.  By comparing with Brownian dynamics simulations I will discuss
the quantitative reliability of the point--like approximation as well as
its regime of validity.

Finally, when the interactions between the confined systems and the
confinement  are non-conservative, as it happens for hydrodynamic
interactions, the interplay between the confined system, say an active
swimmer, and the confinement is more involved. I will, briefly discuss how
such a scenario can be described on the basis of the experienced gained
with the conservative forces.
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