Breather trapping and breather transmission in a DNA model with
an interface |
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Authors: | A Alvarez F R Romero J FR Archilla J Cuevas P V Larsen |
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Institution: | (1) Grupo de Física No Lineal, área de Física Teórica, Facultad de Física, Universidad de Sevilla, Avda. Reina Mercedes, s/n. 41012-, Sevilla, Spain;(2) Grupo de Física No Lineal, Departamento de Física Aplicada I, ETSI Informática, Universidad de Sevilla, Avda. Reina Mercedes, s/n. 41012-, Sevilla, Spain;(3) Department of Mathematics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark |
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Abstract: | We study the dynamics of moving discrete breathers in an interfaced piecewise DNA molecule.
This is a DNA chain in which all the base pairs are identical and
there exists an interface such that the base pairs dipole moments at each side are oriented in opposite
directions.
The Hamiltonian of the Peyrard-Bishop model is augmented with a
term that includes the dipole-dipole coupling between base pairs.
Numerical simulations show the existence of two dynamical regimes.
If the translational kinetic energy of a moving breather launched
towards the interface is below a critical value, it is trapped in
a region around the interface collecting vibrational energy. For
an energy larger than the critical value, the breather is
transmitted and continues travelling along the double strand with
lower velocity. Reflection phenomena never occur.
The same study has been carried out when a single dipole is oriented
in opposite direction to the other ones.
When moving breathers collide
with the single inverted dipole, the same effects appear. These
results emphasize the importance of this simple type of local
inhomogeneity as it creates a mechanism for the trapping of
energy.
Finally, the simulations show that, under favorable conditions,
several launched moving breathers can be trapped successively at the interface
region producing an accumulation of vibrational energy. Moreover,
an additional colliding moving breather can produce a saturation
of energy and a moving breather with all the accumulated energy
is transmitted to the chain. |
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Keywords: | 63 20 Pw Localized modes 63 20 Ry Anharmonic lattice modes 63 50 +x Vibrational states in disordered systems 66 90 +r Other topics in nonelectronic transport properties of condensed matter (restricted to new topics in section 66) |
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