Nonequilibrium Green function approach to photoionization processes in atoms

Nonequilibrium Green function approach to photoionization processes in atoms

We present a quantum kinetic approach for the time-resolved description of many-body e ects in photoionization processes in atoms. The method is based on the non-equilibrium Green functions formalism and solves the Keldysh/Kadano -Baym equations in second Born approximation. An approximation scheme is introduced and discussed, which provides a complete single-particle description of the continu...

Spin Currents in Semiconductor Nanostructures: a Nonequilibrium Green-function Approach

6 SO COUPLINGS IN LOW-DIMENSIONAL SEMICONDUCTORS 10 6.1 Rashba coupling in bulk 2DEG . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.2 Rashba coupling in quantum wires . . . . . . . . . . . . . . . . . . . . . . . . 15 6.2.1 Energy dispersion of Rashba spin-split transverse propagating subbands 15 6.2.2 Spin precession in Rashba quantum wires . . . . . . . . . . . . . . . . . 17 6.3 Di...

Quantum kinetic approach to time-resolved photoionization of atoms

Theoretical approaches to the photoionization of few-electron atoms are discussed. These include nonequilibrium Greens functions and wave function based approaches. In particular, the Multiconfiguration TimeDependent Hartree-Fock method is discussed and applied to a model one-dimensional atom with four electrons. We compute ground state energies and the time-dependent photoionization by the fie...

Conserving Approximations in Nonequilibrium Green Function Theory

In this chapter we introduce the fundamental concepts behind the Green Function Theory. We start from a description of the second quantization method and then, after introducing the ensemble average of an operator, we define the main object of the theory, the Green function. Further on, after obtaining the equation of motion for the Green function, we introduce the self-energy operator and we d...

Double Photoionization of Atoms