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Correlation, nondipole, and entanglement effects in atomic and spin-based systems
This dissertation deals with two different fields of physics, therefore it comprises two different parts. ^ The first part contains three chapters and describes theoretical studies of one of the most fundamental processes in atomic physics, the one-photon double ionization of a He atom. This process represents a prototype for the complete breakup (by absorption of a single photon) of a bound system of three particles, interacting in both the initial (bound) and final (continuum) states by long-range Coulomb interactions. In Chapter 2, electron correlations and the physical mechanisms of the double ionization process are studied by analyzing the fully-differential cross sections within the electric-dipole approximation and within the framework of lowest-order perturbation theory in the interelectron interaction. Chapter 3 is devoted to studies of the influence of nondipole effects (i.e., of the spatial inhomogeneity of the light wave) on the double photoionization process by analyzing the fully-differential cross sections. In Chapter 4, the angle-integrated cross sections for double ionization are analyzed, and two kinds of model-independent parametrizations for such cross sections are derived. ^ The second part of the dissertation (Chapter 5) presents an independent piece of theoretical research at the interface between condensed matter physics and the rapidly developing field of quantum computing and quantum information. This part analyzes entanglement properties of eigenstates of a pair of interacting mesoscopic magnetic quantum dots. Such nanodots are proposed as promising candidates for scalable quantum registers (qubits) designed for storing and manipulating quantum states in a solid state quantum computer. ^ The results presented in Chapters 2, 3, and 5 have been published, while those in Chapter 4 are currently under preparation for submission. ^
Istomin, Andrei Y, "Correlation, nondipole, and entanglement effects in atomic and spin-based systems" (2005). ETD collection for University of Nebraska - Lincoln. AAI3180801.