Emergent properties in an MD simulation
Now that you have gained some familiarity with the behavior of the LJ potential, you will explore a molecular dynamics model in 2D with a number of interacting atoms. The core is the same as the previous model: atoms calculate the force they feel due to the LJ interatomic potential with all the other atoms, are accelerated due to that force and move based on their velocity. With multiple atoms interacting, some properties emerge that are not easy to predict without running a simulation.
An emergent property is a property of a system that doesn’t exist in the entities themselves, but rather, emerges from their interactions. Many of the phenomena in materials science and engineering can be seen as emergent. An example of a non-emergent phenomenon is mass. Each atom has mass and the mass of a material is simply the sum of the masses of its constituent atoms. While almost all phenomena in nature can be viewed as emergent, in our models we can make a clean distinction. We make certain assumptions in the model (these are akin to axioms in mathematics) which are not emergent. In our case, we assume Newtonian objects interacting according to the LJ potential. Any behaviors of the model not encoded directly in those assumptions is “emergent.”