  Collision detection of a large number N of particles can be challenging.
Directly testing N particles for collision among each other leads to N 2
queries. Especially in scenarios, where fast, densely packed particles
interact, challenges arise for classical methods like Particle-in-Cell or
Monte-Carlo. Modern collision detection methods utilising bounding volume
hierarchies are suitable to overcome these challenges and allow a detailed
analysis of the interaction of large number of particles. This approach is
applied to the analysis of the collision of two photon beams leading to the
creation of electron-positron pairs.
