Dresden 2026 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 30: Nonequilibrium Quantum Systems I (joint session TT/DY)
DY 30.10: Talk
Wednesday, March 11, 2026, 12:00–12:15, CHE/0091
Towards Floquet-GW: interacting electrons in time-periodic potentials — •Ayan Pal1,2, Erik G C P Van Loon1,2, and Ferdi Aryasetiawan1,3 — 1Division of Mathematical Physics, Lund University, Professorsgatan 1, 223 63, Lund, Sweden — 2NanoLund, Lund University, Professorsgatan 1, 223 63, Lund, Sweden — 3LINXS Institute of advanced Neutron and X-ray Science, Lund, Sweden
The Floquet theory of time-periodic systems provides a middle ground between equilibrium and far-from-equilibrium physics, making it ideal for studying non-equilibrium steady states. We employ this framework to interacting electrons exposed to spatially and time-periodic potentials by combining Floquet theory with RPA and GW. This is applied to both the homogeneous electron gas and lattice Hamiltonians, allowing us to resolve the interplay between periodic driving, electronic correlations, and collective charge excitations. We compute Floquet-induced Greens function, dielectric function, and screened interaction; and demonstrate the formation of Bloch-Floquet sidebands in the electronic spectral function and in direct and inverse photoemission spectra. The periodic modulation further induces plasmonic sidebands and generates additional Floquet-umklapp regions for the electron-hole continuum. Our analysis highlights how the structure of the travelling drive - frequency, amplitude, and momentum controls the redistribution of spectral weight and the renormalisation of collective modes. This framework provides a route for predicting the plasmonic, dielectric, and optical response properties of weakly to moderately correlated materials under periodic laser driving.
Keywords: Floquet Theory; GW Method; Plasmon; Dielectric Response Function; Non-equillibrium Greens Function