Charge and pairing dynamics in the attractive Hubbard model: Mode coupling and the validity of linear-response theory
- 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 byPump-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.…
Author: | Jörg Bünemann, Götz SeiboldORCiD |
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URL: | https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.245139 |
DOI: | https://doi.org/10.1103/PhysRevB.96.245139 |
ISSN: | 2469-9977 |
ISSN: | 1538-4489 |
Title of the source (English): | Physical Review B |
Document Type: | Scientific journal article peer-reviewed |
Language: | English |
Year of publication: | 2017 |
Tag: | Charge density waves; Hartree-Fock methods; Hubbard model; Linear response theory; Mean field theory; Variational wave functional methods |
Volume/Year: | 96 |
Issue number: | 24 |
Article number: | 245139 |
Faculty/Chair: | Fakultät 1 MINT - Mathematik, Informatik, Physik, Elektro- und Informationstechnik / FG Computational Physics |