TY - GEN A1 - Bünemann, Jörg A1 - Seibold, Götz T1 - Charge and pairing dynamics in the attractive Hubbard model: Mode coupling and the validity of linear-response theory T2 - Physical Review B N2 - Pump-probe experiments have turned out as a powerful tool in order to study the dynamics of competing orders in a large variety of materials. The corresponding analysis of the data often relies on standard linear-response theory generalized to nonequilibrium situations. Here we examine the validity of such an approach for the charge and pairing response of systems with charge-density wave and (or) superconducting (SC) order. Our investigations are based on the attractive Hubbard model which we study within the time-dependent Hartree-Fock approximation. In particular, we calculate the quench and pump-probe dynamics for SC and charge order parameters in order to analyze the frequency spectra and the coupling of the probe field to the specific excitations. Our calculations reveal that the “linear-response assumption” is justified for small to moderate nonequilibrium situations (i.e., pump pulses) in the case of a purely charge-ordered ground state. However, the pump-probe dynamics on top of a superconducting ground state is determined by phase and amplitude modes which get coupled far from the equilibrium state indicating the failure of the linear-response assumption. KW - Charge density waves KW - Hartree-Fock methods KW - Hubbard model KW - Linear response theory KW - Mean field theory KW - Variational wave functional methods Y1 - 2018 UR - https://opus4.kobv.de/opus4-UBICO/frontdoor/index/index/docId/20899 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.245139 SN - 2469-9977 SN - 1538-4489 VL - 96 IS - 24 ER -