Abstract

As an adsorbate moves on a surface, it is constantly feeling the effect of the environment. The environment interactions are felt as a static background interaction, and a frictional force which randomizes the motion and leads to decoherence of the system. For a markovian interaction at short timescales, the frictional force does not directly influence the dynamics of the system, and the overall behaviour becomes deterministic. The short timescale behaviour is known as ballistic motion, depending only on the initial state of the system and a static background interaction. In this talk, we will discuss experimental measurements of ballistic motion of adsorbates using the Spin-Echo technique, which found that the typical rate of ballistic motion was less than would be expected classically. We then use a ‘closed quantum’ simulation to analyse the different factors that contribute to changing the rate of ballistic motion in these systems and discuss the extent to which experimental factors might influence the measurement of ballistic motion.