Following you find a summary on our most relevant findings in the 60 months of the project:
• We have developed a novel, unique and versatile QEDFT which is a reformulation of the Pauli-Fierz quantum field theory in the form of exact quantum Navier-Stokes equations. Besides working on fundamental theoretical and mathematical questions in connection with QEDFTs, we constructed approximations based on extensions of the Kohn-Sham scheme to coupled light-matter situations
• We explored how light-matter coupling produced a combined hybrid state of light and matter – a state which could be utilized in the design of new materials.
• We have demonstrated an ultrafast Lifshitz transition in the correlated type-II Weyl semimetal Td-MoTe2 by combining time-resolved multidimensional photoemission spectroscopy with our state-of-the-art TDDFT plus U simulations [118], possibly leading to the next generation of ultrafast electronic devices
• We have successfully extended electronic structure methods to include the coupling to the photons, showing how strong coupling to photons in an optical cavity changes chemical properties of molecules
• By means of Floquet theory and using high-level computational simulations of material properties we’ve shown how optical transformation via laser-driven can change the topology of a material
• Together with collaborators at CFEL, we showed the possibility of using a new knob to control and optimize the generation of high-order harmonics in bulk materials. We demonstrated that 2D materials can generate high-order harmonics with the same mechanism as atoms and molecules.The new technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials
• We have demonstrated that phonons can be used to induce and control magnetic responses in non-magnetic 2D layers of transition metal dichalcogenides.
• Using state-of-the-art quantum dynamical methods to calculate the quantum of spin or charge Hall conductivity, we’ve successfully classified the intrinsic topological natures of insulators by means of their conductivity itself instead of the mathematically devised topological number.
• We have shown that the transfer of energy and charge between molecules can be drastically enhanced and controlled with virtual photons.
• We have discovered a significant new fundamental kind of quantum electronic oscillation, or plasmons, in atomically thin materials [100]. We found that plasmons behave in a peculiar universal way in all atomically thin materials. These findings have potential implications for novel imaging techniques and for the control of photochemical reactions at the nanoscale.
• In a very recent work [190] we have predicted that a unique laser source could produce highly controllable electric currents in any bulk material. These findings could contribute to the development of superfast, light-controlled electronic switches – the realm of petahertz electronics, where electronic motions need to be controlled both in time and space.
• Condensed Matter Quantum Simulator [138]: Applying the basic concept of moiré interference patterns to 2D crystals has given birth to the fast-growing field of engineering moiré van der Waals heterostructures. Different 2D materials are mixed and matched either at a relative twist angle or for varying chemical compositions to form such moiré interference patterns on the level of their microscopic lattice, which in many cases drastically alters their electronic band structures. This allows us to control their topological features or to promote correlation effects with unprecedented flexibility. The generality of the moiré engineering concept and has recently raised the hope that it provides a condensed matter-based quantum materials design platform of unparalleled versatility [99].
