arXiv subjects

Meng-Bo Luo

Publications and source records attributed to Meng-Bo Luo.

3 recordsLinked to original sources

arXiv2017

Translocation time of a polymer chain through an energy gradient nanopore

The translocation time of a polymer chain through an interaction energy gradient nanopore was studied by Monte Carlo simulations and the Fokker-Planck equation with double-absorbing boundary conditions. Both the simulation and calculation revealed three different behaviors for polymer translocation. These behaviors can be explained qualitatively from free-energy landscapes obtained for polymer translocation at different parameters. Results show that the translocation time of a polymer chain through a nanopore can be tuned by suitably designing the interaction energy gradient.

cond-mat.soft↗

arXiv2015

Numerical study of the depinning transition of a ferromagnetic magnetic domain wall in films

We report first principle numerical study of domain wall (DW) depinning in two-dimensional magnetic film, which is modeled by 2D random-field Ising system with the dipole-dipole interaction. We observe nonconventional activation-type motion of DW and reveal its fractal structure of DW near the depinning transition. We determine scaling functions describing critical dynamics near the transition and obtain universal exponents establishing connection between thermal softening of pinning potential and critical dynamics. We observe that tuning the strength of the dipole-dipole interaction switches DW dynamics between two different universality classes corresponding to two distinct dynamic regimes, motion in the random potential and that in the random force.

cond-mat.stat-mech↗

arXiv2009

Creep motions of flux lines in type II superconductors with point-like defects

We simulated the creep motions of flux lines subject to randomly distributed point-like pinning centers. It is found that at low temperatures, the pinning barrier $U$ defined in the Arrhenius-type $v-F$ characteristics increases with decreasing force $U(F) \propto F^{-μ}$, as predicted by previous theories. The exponent $μ$ is evaluated as $0.28\pm 0.02 $ for the vortex glass and $μ\simeq 0.5\pm 0.02$ for the Bragg glass (BrG). The latter is in good agreement with the prediction by the scaling theory and the functional-renormalization-group theory on creep, while the former is a new estimate. Within BrG, we find that the pinning barrier is suppressed when temperature is lifted to approximately half of the melting temperature. Characterizations of this new transition at equilibrium are also presented, indicative of a phase transition associated with the replica-symmetry breaking.

cond-mat.supr-con↗