Collective decisions are pervasive in every aspect of our society. As shown by Brexit and other recent episodes in European national politics, the way we shape our collective decisions can have far-reaching implications. However, even though there is a vast literature on the aggregation and revision of preferences in and by groups, there are no exact mathematical models of the way groups construct and revise a given decision problem – a process I call constructive deliberation. Getting grip on this political “logic of discovery” is a necessary step towards a suitable combination of information technology with various forms of direct democracy. In this project, I will develop a formal theory of constructive deliberation. Relying on my background in defeasible reasoning and the expertise at the host and secondment institution, I will create mathematical models of individual agents that reason and share information about the decision problem at hand, and show how and when this interaction results in group consensus. This way, the project will complement existing work on collective decision-making, which is in turn necessary for the improvement of democratic processes. In combination with specific training, dissemination, and communication actions, the project will also contribute to my personal development, serving my long-term aim to obtain a permanent position as a researcher (cf. §1.2-1.4).

Efficient daytime cooling without the need for a heat engine is an essential technology to lower our overall energy consumption. Nature offers a chance to off-load heat directly into the cold outer space via the so-called “sky window”: a spectral range from 8 – 13 µm, where our atmosphere is transparent. Concomitantly, solar radiance influx needs to be minimized by scattering and reflection, which would counteract the radiatively removed energy. VISIRday aims to provide ground-breaking new materials and concepts to emit thermal energy directly into this transparent sky window. A radically holistic approach is necessary to understand and design the optical properties of nano- and mesostructured materials over the entire spectral range (300 nm – 20 µm), with the mid-IR sky window being fully emissive, and all other spectral wavelengths being fully reflective. I will therefore combine top-down direct write lithography with intricate bottom-up colloidal self-assembly to device hierarchically structured systems fully addressing these stringent optical properties. A new material class – surface phonon polariton supporting nano- and mesoparticles – with adjustable absorption properties in the mid-IR range, will take a leading role as novel colloidal building block. In combination with polymers and metallic nanostructures my team will demonstrate hybrid structures with finely adjusted and even externally tuneable optical properties. Simulations based on finite element modelling to conceive optimum design rules will complement the experimental work. Inspired by examples from nature, namely white beetles and the Saharan silver ant, I will push the fundamental insights towards novel technologies such as radiative daytime cooling paints and fibres. I am convinced that this project provides the urgently needed materials and concepts to add radiative daytime cooling to the existing mix of green energy technologies.