Groundstates of liquid crystals with colloids: a project for undergraduate students.

Although simulated annealing has become a useful tool for optimization of many systems, its initial raison d'etre of achieving the groundstate structure for a spin or atomic/molecular condensed system remains important. Such modelling, whether using analog models such as glass beads or by invoking simple computer models can be suited to undergraduate projects. In this paper we discuss the application of simulated annealing to find the groundstate of a system of liquid crystals (LC) with suspended colloids. These systems are expected to have interesting conductive behaviour, relevant to applications for television and computer screens. In our first stage, a pure LC system was simulated in python and vizualized by undergraduates and presented on an educational website. In the next stage colloid(s) were added, and the original code modified accordingly. Interesting effects such as ordering around the colloid have been seen and will be described. In the final stage and in order to study larger samples, the code was rewritten in C++ and several algorithmic modifications were made. Speed up factors between 100 and more than 1000 were obtained, and fascinating closed cells surrounding the colloids were observed.