IFIMAR   20926
INSTITUTO DE INVESTIGACIONES FISICAS DE MAR DEL PLATA
Unidad Ejecutora - UE
artículos
Título:
Numerical integration of KPZ equation with restrictions
Autor/es:
TORRES, M F; TORRES, M F; BUCETA, R C; BUCETA, R C
Revista:
JOURNAL OF STATISTICAL MECHANICS-THEORY AND EXPERIMENT
Editorial:
IOP PUBLISHING LTD
Referencias:
Año: 2018 vol. 2018 p. 3320801 - 3320812
ISSN:
1742-5468
Resumen:
In this paper, weintroduce a novel integration method of Kardar-Parisi-Zhang (KPZ) equation. It is known that if during the discrete integration of the KPZ equation the nearest-neighbor height-difference exceeds a critical value, instabilities appear and the integration diverges.One way to avoid these instabilities is to replace the KPZ nonlinear-term by a function of the same term that depends on a single adjustable parameter which is able to control pillars or grooves growing on the interface. Here, we propose a different integration method which consists of directly limiting the value taken by the KPZ nonlinearity, thereby imposing a restriction rule that is applied in each integration time-step, as if it were the growth rule of a restricted discrete model, e.g. restricted-solid-on-solid (RSOS). Taking the discrete KPZ equationwith restrictions to its dimensionless version, the integrationdepends on three parameters: the coupling constant g, the inverse of the time-step k, and the restriction constant ε which is chosen to eliminate divergences while keeping all the properties of the continuous KPZ equation. We study in detail the conditions in the parameters´ space that avoid divergences in the 1-dimensional integration and reproduce the scaling properties of the continuous KPZ with a particular parameter set. We apply the tested methodology to the d-dimensional case ( d = 3, 4 ) with the purpose of obtaining the growth exponent β, by establishing the conditions of the coupling constant g under which we recover known values reached by other authors, particularly for the RSOS model. This method allows usto infer that d = 4 is not the critical dimension of the KPZ universality class, where the strong-coupling phase disappears.p { margin-bottom: 0.25cm; line-height: 120%; }