IoP Lunch Seminar (series)
Come and enjoy a slice of pizza whilst learning about what your fellow colleagues are up to! This months' speakers are Hella Snoek, Bijoy Bera and Rene Gerritsma, who will each give a presentation on what they are currently working on.
Hella Snoek (Staff member) - Tracing particles with the ATLAS detector
Bijoy Bera (Post doc Soft Matter group) - Wetting of Water on Graphene
The wetting properties of graphene have proven controversial and difficult to assess. The presence of a graphene layer on top of a substrate does not significantly change the wetting properties of the solid substrate, suggesting that a single graphene layer does not affect the adhesion between the wetting phase and the substrate. However, wetting experiments of water on graphene show contact angles that imply a large amount of adhesion. Here, we investigate the wetting of graphene by measuring the mass of water vapor adsorbing to graphene flakes of different thickness at different relative humidities. Our experiments unambiguously show that the thinnest of graphene flakes do not adsorb water, from which it follows that the contact angle of water on these flakes is ~180o. Thicker flakes of graphene nanopowder, on the other hand, do adsorb water. A calculation of the van der Waals (vdW) interactions that dominate the adsorption in this system confirms that the adhesive interactions between a single atomic layer of graphene and water are so weak that graphene is superhydrophobic. The observations are confirmed in an independent experiment on graphene-coated water droplets that shows that it is impossible to make liquid ‘marbles’ with molecularly thin graphene.
Rene Gerritsma (Staff member) - Studying quantum physics with mixtures of ultracold atoms and ions
Trapped ultracold atoms and ions are each very suitable to study quantum phenomena since they allow for superb experimental control. However, little work has been done studying mixtures of ultracold atoms and ions. This is mostly because it has proven very hard to reach the temperatures required to observe quantum phenomena in these systems. In my talk I will address the question of whether an ultracold atom-ion mixture could be used in quantum technology, such as a quantum simulator. The idea is that the ultracold (fermionic) atoms play the role of electrons, while the trapped ions self-assemble into a crystal supporting quantised phonon modes which in turn interact with the atoms. In this way, a natural crystaline solid could be simulated. I will also discuss which approaches we take in the lab to create such a hybrid system in the ultracold mixture.