Convex splitting method for the calculation of transition states of energy functional

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Detail(s)

Original languageEnglish
Pages (from-to)417-434
Journal / PublicationJournal of Computational Physics
Volume353
Online published24 Oct 2017
Publication statusPublished - 15 Jan 2018

Abstract

Among numerical methods for partial differential equations arising from steepest descent dynamics of energy functionals (e.g., Allen–Cahn and Cahn–Hilliard equations), the convex splitting method is well-known to maintain unconditional energy stability for a large time step size. In this work, we show how to use the convex splitting idea to find transition states, i.e., index-1 saddle points of the same energy functionals. Based on the iterative minimization formulation (IMF) for saddle points [14], we introduce the convex splitting method to minimize the auxiliary functional at each cycle of the IMF. We present a general principle of constructing convex splitting forms for these auxiliary functionals and show how to avoid solving nonlinear equations. The new numerical scheme based on the convex splitting method allows for large time step sizes. The new methods are tested for the one dimensional Ginzburg–Landau energy functional in the search of the Allen–Cahn or Cahn–Hilliard types of transition states. We provide the numerical results of transition states for the two dimensional Landau–Brazovskii energy functional for diblock copolymers.

Research Area(s)

  • Transition state, Saddle point, Convex splitting method, Iterative minimization formulation