Three-dimensional Finite Difference-Time Domain Solution of Dirac Equation

Single-cone real-space finite difference scheme for the time-dependent Dirac equation

A finite difference scheme for the numerical treatment of the (3+1)D Dirac equation is presented. Its staggered-grid intertwined discretization treats space and time coordinates on equal footing, thereby avoiding the notorious fermion doubling problem. This explicit scheme operates entirely in real space and leads to optimal linear scaling behavior for the computational effort per space-time grid-point. It allows for an easy and efficient parallelization. A functional for a norm on the grid is identified. It can be interpreted as probability density and is proved to be conserved by the scheme.…

单锥实空间有限差分方案用于Dirac von Neumann方程

Single-cone real-space finite difference schemes for the Dirac von Neumann equation

本文提出两种单锥交错时空网格方案用于求解(2+1)D Dirac哈密顿量的von Neumann方程，第一种基于密度算符的

A dispersion and norm preserving finite difference scheme with transparent boundary conditions for the Dirac equation in (1+1)D

A finite difference scheme is presented for the Dirac equation in (1+1)D. It can handle space- and time-dependent mass and potential terms and utilizes exact discrete transparent boundary conditions (DTBCs). Based on a space- and time-staggered leap-frog scheme it avoids fermion doubling and preserves the dispersion relation of the continuum problem for mass zero (Weyl equation) exactly. Considering boundary regions, each with a constant mass and potential term, the associated DTBCs are derived by first applying this finite difference scheme and then using the Z-transform in the discrete time …

Optimizing the domain wall fermion Dirac operator using the R-Stream source-to-source compiler

The application of the Dirac operator on a spinor field, the Dslash operation, is the most computation-intensive part of the lattice QCD simulations. It is often the key kernel to optimize to achieve maximum performance on various platforms. Here we report on a project to optimize the domain wall fermion Dirac operator in Columbia Physics System (CPS) using the R-Stream source-to-source compiler. Our initial target platform is the Intel PC clusters. We discuss the optimization strategies involved before and after the automatic code generation with R-Stream and present some preliminary benchmar…

A domain-specific language and matrix-free stencil code for investigating electronic properties of Dirac and topological materials

We introduce PVSC-DTM (Parallel Vectorized Stencil Code for Dirac and Topological Materials), a library and code generator based on a domain-specific language tailored to implement the specific stencil-like algorithms that can describe Dirac and topological materials such as graphene and topological insulators in a matrix-free way. The generated hybrid-parallel (MPI+OpenMP) code is fully vectorized using Single Instruction Multiple Data (SIMD) extensions. It is significantly faster than matrix-based approaches on the node level and performs in accordance with the roofline model. We demonstrate…

New $N_f=2$ Pseudofermion Action for Monte-Carlo Simulation of Lattice Field Theory with Domain-Wall Fermions

We construct a novel $ N_f = 2 $ pseudofermion action for Monte-Carlo simulation of lattice gauge theory with domain-wall fermions (DWF), of which the effective four-dimensional lattice Dirac operator is equal to the overlap-Dirac operator with the argument of the sign function equal to $ H = c γ_5 D_w (1 + d D_w)^{-1} $, where $ c $ and $ d $ are parameters, and $D_w$ is the standard Wilson-Dirac operator plus a negative parameter $-m_0 \; (0 < m_0 < 2)$. This new action is particularly useful for the challenging simulations of lattice gauge theories with large $N_f = 2n $ DWF, on the large l…