A novel collision rule for active rough particles
Systems of hard spheres (HS) are a popular model to describe liquids.
These are especially well suited for modeling dense systems, where the hard core repulsion of the atoms is the dominant effect.
Computer simulations by standard methods of numerical integration would fail, because of the discontinuity of the HS potential.
That is why we use a self developed code to perform event driven simulations, a special approach for HS-simulations to prevent overlaps at all times.
The HS model in its simplest form describes perfectly smooth spheres, that reflect each other in a collision event.
A slightly more sophisticated extension are perfectly rough spheres, allowing for rotation-translation coupling.
This project uses a new collision protocol, that just sightly alters the model from above: while keeping everything else intact, it breaks time inversion symmetry with staggering implications.
Breaking time inversion symmetry leads to a non-equilibrium system, which turns the intuition gained from simple equilibrium liquids upside down.