My active research is on the dynamics of wetting. Although the field has seen a lot of interest over the last decades, there is still a wealth of unanswered questions about which dynamics dominate at the triple contact line of droplets. This is in part due to the difficulty of observing molecular processes in regular laboratory experiments.
Thanks to recent developments of efficient molecular simulation software and the increased availability of sufficient computational power, we use molecular dynamics to observe systems of sizes approaching micrometer length scales. By modeling systems which bridge molecular and macroscopic physics we can study processes of wetting in great detail.
For my master’s project at Umeå University I studied the quantum electrodynamical (QED) effect of pair annihilation inside extreme laser fields. This effect relates to the constant creation and annihilation of virtual particles in space—or, the quantum vacuum. Since energy cannot be created from nothing, these virtual particles exist only as a short-lived fluctuation. However, if during this short life-span the virtual pair absorbs the energy required to create their mass (E = 2mc2), they can split apart and become real particles. This phenomena is known as Schwinger pair production and can be observed in extremely strong electric fields, where an abundance of photons are used to provide the required energy.
This project studied a similar effect, wherein two particles in a strong electric field annihilate to emit a single photon—a channel which is normally prohibited, as it violates momentum conservation. However, by interacting with some number of photons inside a background field, the momentum conservation for the single-photon emission can be satisified for the particle pair.
We calculated the channel’s cross section for two modern, extremely powerful laser facilities: the European XFEL and ELI infrastructures. We found that the channel should be present in the XFEL field under very finely tuned experimental set-ups, but that it is not visible at the ELI sites.
In quantum physics, a particle’s spin leads to many interesting phenomena. One such is spin–orbit coupling, which in an external field can cause splitting of energy levels, creating a fine structure. My bachelor’s project studied the effect of this on Langmuir waves in magnetised plasmas, following a recently developed theory of quantum plasmas.