A co-simulation technique for efficient particle tracking using hybrid numerical methods with application in high energy physics

Abstract

Particle tracking in physical systems is a well known simulation challenge in many domains. In particular, High Energy Physics (HEP) demand efficient simulations of charged particles moving throughout complex detector geometries in a magnetic field. Quantized State Systems (QSS) is a modern family of hybrid numerical methods that provides attractive performance features for these problems. Its state-of-the-art implementation is the general-purpose QSS Solver toolkit. Meanwhile, Geant4 is the most widely used platform for computational particle physics, embedding vast amounts of physics domain knowledge. Yet, Geant4 relies rigidly on classic discrete time numerical methods. In this work we present a robust co-simulation technique to apply QSS in the simulation of HEP experiments, thus leveraging the best of both toolkits. We obtained speedups of up to three times in synthetic, yet representative scenarios, and a competitive performance in a difficult benchmark modeled after the Compact Muon Solenoid (CMS) particle detector at CERN.