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We present the multi-channel Dyson equation that combines two or more many-body Green's functions to describe the electronic structure of materials. In this thesis, we use it to model photoemission spectra by coupling the one-body Green's function with the three-body Green's function and to model neutral excitation by coupling the two-body Green's function with the four-body Green's function . We demonstrate that, unlike methods using only the one-body Green's function, our approach puts the description of quasiparticles and satellites on an equal footing. We propose a multi-channel self-energy that is static and only contains the bare Coulomb interaction, making frequency convolutions and self-consistency unnecessary. Despite its simplicity, we demonstrate with a diagrammatic analysis that the physics it describes is extremely rich. Finally, we present a framework based on an effective Hamiltonian that can be solved for any many-body system using standard numerical tools. We illustrate our approach by applying it to the Hubbard dimer and show that it is exact both at 1/4 and 1/2 filling.
We present the second release of the real-time time-dependent density functional theory code “Quantum Dissipative Dynamics” (QDD). It augments the first version [1] by a parallelization on a GPU coded with CUDA fortran. The extension focuses on the dynamical part only because this is the most time consuming part when applying the QDD code. The performance of the new GPU implementation as compared to OpenMP parallelization has been tested and checked on a couple of small sodium clusters and small covalent molecules. OpenMP parallelization allows a speed-up by one order of magnitude in average, as compared to a sequential computation. The use of a GPU permits a gain of an additional order of magnitude. The performance gain outweighs even the larger energy consumption of a GPU. The impressive speed-up opens the door for more demanding applications, not affordable before
We present the multi-channel Dyson equation that combines two or more many-body Green's functions to describe the electronic structure of materials. In this work we use it to model photoemission spectra by coupling the one-body Green's function with the three-body Green's function. We demonstrate that, unlike methods using only the one-body Green's function, our approach puts the description of quasiparticles and satellites on an equal footing. We propose a multi-channel self-energy that is static and only contains the bare Coulomb interaction, making frequency convolutions and self-consistency unnecessary. Despite its simplicity, we demonstrate with a diagrammatic analysis that the physics it describes is extremely rich. Finally, we present a framework based on an effective Hamiltonian that can be solved for any many-body system using standard numerical tools. We illustrate our approach by applying it to the Hubbard dimer and show that it is exact both at 1/4 and 1/2 filling.
We derive the explicit expression of the three self-energies that one encounters in many-body perturbation theory: the well-known $GW$ self-energy, as well as the particle-particle and electron-hole $T$-matrix self-energies. Each of these can be easily computed via the eigenvalues and eigenvectors of a different random-phase approximation (RPA) linear eigenvalue problem that completely defines their corresponding response function. For illustrative and comparative purposes, we report the principal ionization potentials of a set of small molecules computed at each level of theory.
Sujets
CAO
Electronic properties of sodium and carbon clusters
Electric field
Explosion coulombienne
Plasmon resonance
Nanoplasma
FOS Physical sciences
Plasmon
Lasers intenses
Electronic emission
Embedded metal cluster
Ionization mechanisms
Green's function
Coulomb explosion
Corrélations
Matel clusters
3640Cg
Interactions de photons avec des systèmes libres
Numbers 3360+q
Pump-and-probe
R2S
Propriétés électroniques d'agrégats métalliques et de molécules organiques
Neutronique
RDMFT
Photon interactions with free systems
Agregats
Dynamique moléculaire
Laser
Modèle de Hubbard
TDDFT
Density-functional theory
Relaxation
Ar environment
MBPT
Molecular dynamics
Instability
Dynamics
Metal cluster
Diffusion
Hubbard model
Radiations
Phénomènes dépendant du temps processus d'excitation et de relaxation
Molecules
Time-dependent density-functional theory
Instabilité
Effets dissipatifs
High intensity lasers
Hierarchical method
Irradiation moléculaire
Matrice densité
Molecular irradiation
Angle-resolved photoelectron spectroscopy
Landau damping
Extended time-dependent Hartree-Fock
Coulomb presssure
Semiclassic
Neutronic
Hierarchical model
Nucléaire
Neutron Induced Activation
3115ee
Optical response
Théorie de la fonctionnelle de la densité
Collisional time-dependent Hartree-Fock
Electronic excitation
Nuclear
Electron correlation
Density Functional Theory
Correction d'auto-interaction
Electron emission
Fonction de Green
Inverse bremsstrahlung collisions
Corrélations dynamiques
Metal clusters
Méchanismes d'ionisation
Atom laser
Monte-Carlo
Electron-surface collision
Clusters
Propriétés électroniques d'agrégats de sodium et de carbone
Champ-moyen
Dissipative effects
Activation neutronique
Photo-electron distributions
Dissipation
Aggregates
Mean-field
Au-delà du champ moyen
Damping
Deposition
Energy spectrum
Photo-Electron Spectrum
Agrégats
Fission
Collision frequency
Electronic properties of metal clusters and organic molecules
Chaos
Environment
Deposition dynamics
3620Kd