Time-Dependent GW Calculations for Thousands of Atoms

Out-of-equilibrium quantum materials remain notoriously hard to describe and model, as strong, ultrafast excitations invalidate near-equilibrium approximations and demand the accurate inclusion of many-body interactions and memory effects. We present a scalable method that enables simulating the nonequilibrium dynamics of excited nanostructures containing thousands of atoms. Our NEGF-QF approach [1-4] is a quantum-fluctuation extension of nonequilibrium Green's function (NEGF) theory that enables highly efficient time-dependent nonadiabatic GW calculations, capturing correlations effects beyond mean-field such as the dynamical buildup of long-range screening. We demonstrate the method by tracking the creation of excitons following optical excitation of topological edge states in large carbon nanostructures, resolving their formation dynamics and timescales [5]. This framework opens a predictive route to realistic, first-principles modeling of complex ultrafast phenomena in mesoscale quantum materials.

[1] N. Schlünzen, J.-P. Joost, M. Bonitz, Phys. Rev. Lett. 124, 076601 (2020)

[2] J.-P. Joost, N. Schlünzen, M. Bonitz, Phys. Rev. B 101, 245101 (2020)

[3] E. Schroedter, J.-P. Joost, M. Bonitz, Cond. Matt. Phys. 25, 23401 (2022)

[4] E. Schroedter, B. Wurst, J.-P. Joost, M. Bonitz, Phys. Rev. B 108, 205109 (2023)

[5] J.-P. Joost, E. Schroedter, M.Bonitz, in preparation