6533b7d7fe1ef96bd1267b70
RESEARCH PRODUCT
The Kadanoff–Baym approach to double excitations in finite systems
M. ManninenNiko SäkkinenR Van Leeuwensubject
PhysicsQuantum PhysicsCondensed Matter - Mesoscale and Nanoscale PhysicsStrongly Correlated Electrons (cond-mat.str-el)Nuclear TheoryExcitation spectraFinite systemFOS: Physical sciencesGeneral Physics and AstronomySpectral lineCondensed Matter - Strongly Correlated ElectronsLattice (order)Mesoscale and Nanoscale Physics (cond-mat.mes-hall)Sum rule in quantum mechanicsBorn approximationQuantum Physics (quant-ph)Mathematical physicsdescription
We benchmark many-body perturbation theory by studying neutral, as well as non-neutral, excitations of finite lattice systems. The neutral excitation spectra are obtained by time-propagating the Kadanoff-Baym equations in the Hartree-Fock and second Born approximations. Our method is equivalent to solving the Bethe-Salpeter equation with a high-level kernel while respecting self-consistently, which guarantees the fulfillment of a frequency sum rule. As a result, we find that a time-local method, such as Hartree-Fock, can give incomplete spectra, while already the second Born, which is the simplest time-nonlocal approximation, reproduces well most of the additional excitations, which are characterized as double-excitations.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2011-08-20 | New Journal of Physics |