QSW_MPI: A framework for parallel simulation of quantum stochastic walks

Abstract

QSW_MPI is a Python package developed for time-series simulation of continuous-time quantum stochastic walks. This model allows for the study of Markovian open quantum systems in the Lindblad formalism, including a generalisation of the continuous-time random walk and continuous-time quantum walk. Consisting of a Python interface accessing parallelised Fortran libraries utilising sparse data structures, QSW_MPI is scalable to massively parallel computers, which makes possible the simulation of a wide range of walk dynamics on directed and undirected graphs of arbitrary complexity. Program summaryProgram Title: QSW_MPICPC Library link to program files:http://dx.doi.org/10.17632/r8jsx4xxgv.1Licensing provisions: GPLv3Programming language: Python 3 + Fortran 2003External routines/libraries: NumPy [1], SciPy [2], MPI for Python [3], h5py[4]Nature of problem: QSW_MPI provides a framework for the simulation of quantum stochastic walks on arbitrary graphs (directed/undirected, weighted/unweighted).Solution method: A parallel distributed-memory implementation of the matrix exponential via a truncated Taylor series expansion with scaling and squaring [5].Additional comments including restrictions and unusual features: QSW_MPI will provide support for the simulation of multiple quantum walkers in a future version.