arXiv subjects

S. Y. Yoon

Publications and source records attributed to S. Y. Yoon.

5 recordsLinked to original sources

arXiv2006

Continuously varying exponents in $A+B \to 0$ reaction with long-ranged attractive interaction

We investigate the kinetics of the $A+B \to 0$ reaction with long-range attractive interaction $V(r) \sim -r^{-2σ}$ between $A$ and $B$ or with the drift velocity $v \sim r^{-σ}$ in one dimension, where $r$ is the closest distance between $A$ and $B$. It is analytically show that the dynamical exponents for density of particles ($ρ$) and the size of domains ($\ell$) continuously vary with $σ$ when $σ< σ_c =/1/2$, while that for the distance between adjacent opposite species ($\ell_{AB}$) varies when $σ< σ_c^{AB}= 7/6$. Beyond $σ_c^{AB}$, diffusive motions dominate the kinetics, so that the dynamical behavior for diffusive systems is completely recovered. These anomalous behaviors with the two crossover values of $σ$ are supported by numerical simulations and the argument of effective repulsion between the opposite species domains.

cond-mat.stat-mech↗

arXiv2005

Correlation functions and queuing phenomena in growth processes with drift

We suggest a novel stochastic discrete growth model which describes the drifted Edward-Wilkinson (EW) equation $\partial h /\partial t = ν\partial_x^2 h - v\partial_x h +η(x,t)$. From the stochastic model, the anomalous behavior of the drifted EW equation with a defect is analyzed. To physically understand the anomalous behavior the height-height correlation functions $C(r)=< |h({x_0}+r)-h(x_0)|>$ and $G(r)=< |h({x_0}+r)-h(x_0)|^2>$ are also investigated, where the defect is located at $x_0$. The height-height correlation functions follow the power law $C(r)\sim r^{α'}$ and $G(r)\sim r^{α''}$ with $α'=α''=1/4$ around a perfect defect at which no growth process is allowed. $α'=α''=1/4$ is the same as the anomalous roughness exponent $α=1/4$. For the weak defect at which the growth process is partially allowed, the normal EW behavior is recovered. We also suggest a new type queuing process based on the asymmetry $C(r) \neq C(-r)$ of the correlation function around the perfect defect.

cond-mat.stat-mech↗

arXiv2005

Flux fluctuations in a multi-random-walker model and surface growth dynamics

We study the dynamics of visitation flux in a multi-random-walker model by comparison to surface growth dynamics in which one random walker drops a particle to a node at each time the walker visits the node. In each independent experiment (trial or day) for the multi-random-walker model, the number of walkers are randomly chosen from the uniform distribution $[< N_{RW} > -\triangle N_{RW}, < N_{RW} > +\triangle N_{RW} ]$. The averaged fluctuation $\bar σ ({T_{RW}})$ of the visitations over all nodes $i$ and independent experiments is shown to satisfy the power-law dependence on the walk step $T_{RW}$ as $\bar σ ({T_{RW}})\simeq {T_{RW}}^β$. Furthermore two distinct values of the exponent $β$ are found on a scale-free network, a random network and regular lattices. One is $β_i$, which is equal to the growth exponent $β$ for the surface fluctuation $W$ in one-random-walker model, and the other is $β=1$. $β_i$ is found for small $\triangle N_{RW}$ or for the system governed by the internal intrinsic dynamics. In contrast $β=1$ is found for large $\triangle N_{RW}$ or for the system governed by the external flux variations. The implications of our results to the recent studies on fluctuation dynamics of the nodes on networks are discussed.

cond-mat.stat-mech↗

arXiv2005

Anomalous kinetics of attractive $A+B \to 0$ reactions

We investigate the kinetics of $A+B \to 0$ reaction with the local attractive interaction between opposite species in one spatial dimension. The attractive interaction leads to isotropic diffusions inside segregated single species domains, and accelerates the reactions of opposite species at the domain boundaries. At equal initial densities of $A$ and $B$, we analytically and numerically show that the density of particles ($ρ$), the size of domains ($\ell$), the distance between the closest neighbor of same species ($\ell_{AA}$), and the distance between adjacent opposite species ($\ell_{AB}$) scale in time as $ρ\sim t^{-1/3}$, $\ell_{AA} \sim t^{1/3}$, and $\ell \sim \ell_{AB} \sim t^{2/3}$ respectively. These dynamical exponents form a new universality class distinguished from the class of uniformly driven systems of hard-core particles.

cond-mat.stat-mech↗

arXiv2002

Fluctuations of self-flattening surfaces

We study the scaling properties of self-flattening surfaces under global suppression on surface fluctuations. Evolution of self-flattening surfaces is described by restricted solid-on-solid type monomer deposition-evaporation model with reduced deposition (evaporation) at the globally highest (lowest) site. We find numerically that equilibrium surface fluctuations are anomalous with roughness exponent $α\simeq 1/3$ and dynamic exponent $z_W \simeq 3/2$ in one dimension (1D) and $α=0 (\log)$ and $z_W \simeq 5/2$ in 2D. Stationary roughness can be understood analytically by relating our model to the static self-attracting random walk model and the dissociative dimer type deposition-evaporation model. In case of nonequilibrium growing/eroding surfaces, self-flattening dynamics turns out to be irrelevant and the normal Kardar-Parisi-Zhang universality is recovered in all dimensions.

cond-mat.stat-mech↗