Computer simulations that predict the light-induced change in the physical and chemical properties of complex systems, molecules, nanostructures and solids usually ignore the quantum nature of light. We have recently shown how the effects of the photons can be properly included in such calculations. The basic idea is to treat the full QED system of particles and photons as a quantum fluid. Here the particles are represented by a charge current, and the photons by a classical electromagnetic field that acts on the current in a very complex manner. This study opens up the possibility to predict and control the change of material properties due to the interaction with light particles from first principles.
The quantum nature of light does usually not play an important role when considering the chemical properties of atoms or molecules. however, under certain conditions photons can strongly influence chemistry. Upon placing a molecule between two strongly reflecting mirrors, a so-called optical cavity, the quantum nature of the electromagnetic field can become important. In such situation single photons can interact unusually strongly with the molecule, and one can no longer distinguish between molecule and photons. The properties of this new state of matter can be very different to the bare molecule, We will apply this new theoretical methods to more complex molecules. The goal is to show that the current results are generally valid and that one can alter the chemical properties of all sorts of different molecules via strong light-matter coupling.
We will discuss the theoretical approaches developed in the group for the characterisation of matter out of equilibrium, the control material processes at the electronic level and tailor material properties, and master energy and information on the nanoscale to propose new devices with capabilities. We will focus on examples linked to the efficient conversion of light into electricity or chemical fuels (“artificial photosynthesis”) and the design on new nanostructure based optoelectronic devices, among others.
Our goal is to provide a detailed, efficient, and at the same time accurate microscopic approach for the ab-initio description and control of the dynamics of decoherence and dissipation in quantum many-body systems. This theoretical framework provides a new way to control and alter chemical reactions in complex systems, direct the moveme of electrons, selectively trigger physico-chemical processes, and create new state of mater.