A simple derivation of the exact quasiparticle theory and its extension to arbitrary initial excited eigenstates

Abstract

The quasiparticle (QP) energies, which are minus of the energies required by removing or produced by adding one electron from/to the system, corresponding to the photoemission or inverse photoemission (PE/IPE) spectra, are determined together with the QP wave functions, which are not orthonormal and even not linearly independent but somewhat similar to the normal spin orbitals in the theory of the configuration interaction, by self-consistently solving the QP equation coupled with the equation for the self-energy. The electron density, kinetic and all interaction energies can be calculated using the QP wave functions. We prove in a simple way that the PE/IPE spectroscopy and therefore this QP theory can be applied to an arbitrary initial excited eigenstate. In this proof, we show that the energy-dependence of the self-energy is not an essential difficulty, and the QP picture holds exactly if there is no relaxation mechanism in the system. The validity of the present theory for some initial excited eigenstates is tested using the one-shot GW approximation for several atoms and molecules.

arXiv comment32 pages, 6 figures

References in corpus (8)

• Current-dependent exchange-correlation potential for dynamical linear response theory
• Center of mass and relative motion in time dependent density functional theory
• Electron affinity of Li: A state-selective measurement
• First-principle study of excitonic self-trapping in diamond
• Exact exchange-correlation potential for a time-dependent two electron system
• Time-Dependent Density-Functional Theory of Strong-Field Ionization of Atoms under Soft X-Rays
• Efficient Total Energy Calculations from Self-Energy Models
• GWΓ + Bethe-Salpeter equation approach for photoabsorption spectra: Importance of self-consistent GWΓ calculations in small atomic systems