1,364 research outputs found
Non-equilibrium Green's function approach to inhomogeneous quantum many-body systems using the Generalized Kadanoff Baym Ansatz
In non-equilibrium Green's function calculations the use of the Generalized
Kadanoff-Baym Ansatz (GKBA) allows for a simple approximate reconstruction of
the two-time Green's function from its time-diagonal value. With this a drastic
reduction of the computational needs is achieved in time-dependent
calculations, making longer time propagation possible and more complex systems
accessible. This paper gives credit to the GKBA that was introduced 25 years
ago. After a detailed derivation of the GKBA, we recall its application to
homogeneous systems and show how to extend it to strongly correlated,
inhomogeneous systems. As a proof of concept, we present results for a
2-electron quantum well, where the correct treatment of the correlated electron
dynamics is crucial for the correct description of the equilibrium and dynamic
properties
Fluid Modes of a Spherically Confined Yukawa Plasma
The normal modes of a three-dimensional Yukawa plasma in an isotropic,
harmonic confinement are investigated by solving the linearized cold fluid
equations. The eigenmodes are found analytically and expressed in terms of
hypergeometric functions. It is found that the mode frequencies solely depend
on the dimensionless plasma parameter , where is the plasma
radius and the inverse screening length. The eigenfrequencies increase
monotonically with and saturate in the limit . Compared
with the results in the Coulomb limit~[D. H. E. Dubin, Phys. Rev. Lett.
\textbf{66}, 2076 (1991)], we find a new class of modes characterized by the
number which determines the number of radial nodes in the perturbed
potential. These modes originate from the degenerate bulk modes of the Coulomb
system. Analytical formulas for the eigenfrequencies are derived for limiting
cases
Ground state of a confined Yukawa plasma
The ground state of an externally confined one-component Yukawa plasma is
derived analytically. In particular, the radial density profile is computed.
The results agree very well with computer simulations on three-dimensional
spherical Coulomb crystals. We conclude in presenting an exact equation for the
density distribution for a confinement potential of arbitrary geometry.Comment: 5 pages, 4 figure
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