Belgian science does not often make an appearance here perhaps due to language issues or the direction that science research has taken in that country or something else. In any event, a Feb. 3, 2014 news item on Nanowerk highlights some graphene research taking place in Belgium (Note: A link has been removed),
Belgian scientists have used a particle physics theory to describe the behaviour of particle-like entities, referred to as excitons, in two layers of graphene, a one-carbon-atom-thick honeycomb crystal. In a paper published in EPJ B (“Exciton swapping in a twisted graphene bilayer as a solid-state realization of a two-brane model”), Michael Sarrazin from the University of Namur, and Fabrice Petit from the Belgian Ceramic Research Centre in Mons, studied the behaviour of excitons in a bilayer of graphene through an analogy with excitons evolving in two abstract parallel worlds, described with equations typically used in high-energy particle physics.
I found the previous description a little more confusing that I’d hoped but do feel that this line present in the Jan. 21, 2014 EPJ B news release (also on EurekAlert but dated Feb. 3, 2014) helped clarify matters,
Equations used to describe parallel worlds in particle physics can help study the behaviour of particles in parallel graphene layers
One of the problems with skimming through material as I often do is that more complex sentences cause confusion and whoever removed the first line from the news item was relying on me (the reader) to carefully read through some 70 to 80 words before revealing that the scientists had created two parallel virtual worlds to test their theory. Once that was understood, this made more sense (from the news release),
The authors used the equations reflecting a theoretical world consisting of a bi-dimensional space sheet—a so-called brane—embedded in a space with three dimensions. Specifically, the authors described the quantum behaviour of excitons in a universe made of two such brane worlds. They then made an analogy with a bilayer of graphene sheets, in which quantum particles live in a separate space-time.
They showed that this approach is adapted to study theoretically and experimentally how excitons behave when they are confined within the plane of the graphene sheet.
Sarrazin and his colleague have also theoretically shown the existence of a swapping effect of excitons between graphene layers under specific electromagnetic conditions. This swapping effect may occur as a solid-state equivalent of known particle swapping predicted in brane theory.
To verify their predictions, the authors suggest the design for an experimental device relying on a magnetically tunable optical filter. It uses magnets whose magnetic fields can be controlled with a separate external magnetic field. The excitons are first produced by shining an incident light onto the first graphene layer. The device then works by recording photons in front of the second graphene layer, which provide a clue of the decay of the exciton after it has swapped onto the second layer from the first.
Here’s a link to and a citation for the paper,
M. Sarrazin and F. Petit (2014), Exciton swapping in a twisted graphene bilayer as a solid-state realization of a two-brane model, European Physical Journal B, DOI 10.1140/epjb/e2013-40492-5
Clicking on the link will lead you directly to this open access paper.