Short-time dynamics and magnetic critical behavior of the two-dimensional random-bond Potts model

Flow through a narrow bent channel may induce topological rearrangements in a two-dimensional monodispersed dry liquid foam. We use the Cellular Potts Model to simulate a foam under a variable driving force in order to investigate the strain-rate response from these rearrangements. We observe a set of foams' behaviors ranging from elastic, viscoelastic to fluid regime. Bubble's topological rearrangements are localized and their cumulative rearrangements change linearly with time, thus nonavalanches critical behavior is found. The strain-rate affects the rate of topological rearrangements, its dependence on the drag force is nonlinear, obeying a Herschel–Bulkley-like relationship below the foam's flow point.

Download Full-text

ANALYSIS OF CRITICAL SHORT-TIME LANGEVIN DYNAMICS IN TWO-DIMENSIONAL ϕ4 THEORY ON THE BASIS OF A HIGHER-ORDER ALGORITHM

International Journal of Modern Physics C ◽

10.1142/s0129183109013959 ◽

2009 ◽

Vol 20 (05) ◽

pp. 735-745

Author(s):

TSUYOSHI OTOBE ◽

HIROMICHI NAKAZATO ◽

KEISUKE OKANO ◽

KAZUYA YUASA ◽

NOZOMU HATTORI

Keyword(s):

Critical Point ◽

Langevin Dynamics ◽

Initial Increase ◽

Two Dimensional ◽

Relaxation Dynamics ◽

Time Dynamics ◽

Time Scaling ◽

Langevin Simulation ◽

Short Time ◽

Order Algorithm

We investigate the critical short-time scaling of the two-dimensional lattice ϕ4 field theory with a Langevin dynamics. Starting from a "hot" initial configuration but with a small magnetization, the critical initial increase of the magnetization is observed, through which we determine the critical point. From the short-time relaxation dynamics of various quantities at the critical point obtained, the dynamic critical exponents θ, z and the static exponent β/ν are evaluated. In executing a Langevin simulation, an appropriate discretization method with respect to the time degree of freedom becomes essentially important to be adopted and we show that the well-known second-order form of discretized Langevin equation works well to investigate the short-time dynamics.

Download Full-text

SHORT TIME CORRELATIONS IN A TWO-DIMENSIONAL ISING MODEL WITH A LINE OF DEFECTS

Modern Physics Letters B ◽

10.1142/s0217984901002919 ◽

2001 ◽

Vol 15 (25) ◽

pp. 1141-1146 ◽

Cited By ~ 4

Author(s):

T. TOMÉ ◽

C. S. SIMÕES ◽

J. R. DRUGOWICH DE FELÍCIO

Keyword(s):

Monte Carlo ◽

Critical Temperature ◽

Ising Model ◽

Early Time ◽

Time Correlation ◽

Two Dimensional ◽

Time Dynamics ◽

Time Correlations ◽

Time Regime ◽

Short Time

We study the short time dynamics of a two-dimensional Ising model with a line of defects. The dynamical critical exponent θ associated to the early time regime at the critical temperature was obtained by Monte Carlo simulations. The exponent θ was estimated by a method where the quantity of interest is the time correlation of the magnetization.

Download Full-text