Recent developments in the method of different orbitals for different spins

Alternate molecular orbital and nonpaired spatial orbital methods compared for conjugate organic compound

The Crossover between Liquid and Solid Electron Phases in Quantum Dots: A Large-Scale Configuration-Interaction Study

We study the crossover between liquid and solid electron phases in a two-dimensional harmonic trap as the density is progressively diluted. We infer the formation of geometrically ordered phases from charge distributions and pair correlation functions obtained via a large scale configuration interaction calculation.Comment: LaTeX 2e, Elsevier style. Four pages, two b/w postscript figures. Submitted to Computer Physics Communications as a proceeding of Conference on Computational Physics, Genova 200

Three-electron anisotropic quantum dots in variable magnetic fields: exact results for excitation spectra, spin structures, and entanglement

Exact-diagonalization calculations for N=3 electrons in anisotropic quantum dots, covering a broad range of confinement anisotropies and strength of inter-electron repulsion, are presented for zero and low magnetic fields. The excitation spectra are analyzed as a function of the strength of the magnetic field and for increasing quantum-dot anisotropy. Analysis of the intrinsic structure of the many-body wave functions through spin-resolved two-point correlations reveals that the electrons tend to localize forming Wigner molecules. For certain ranges of dot parameters (mainly at strong anisotropy), the Wigner molecules acquire a linear geometry, and the associated wave functions with a spin projection S_z=1/2 are similar to the representative class of strongly entangled states referred to as W-states. For other ranges of parameters (mainly at intermediate anisotropy), the Wigner molecules exhibit a more complex structure consisting of two mirror isosceles triangles. This latter structure can be viewed as an embryonic unit of a zig-zag Wigner crystal in quantum wires. The degree of entanglement in three-electron quantum dots can be quantified through the use of the von Neumann entropy.Comment: To appear in Physical Review B. REVTEX4. 13 pages with 16 color figures. To download a copy with higher-quality figures, go to publication #78 in http://www.prism.gatech.edu/~ph274cy

Evaluating the Impact of Intimate Partner Violence:a comparison of men in treatment and their (ex-) partners accounts

Intimate partner violence (IPV) is a public health and widespread problem, and perpetrator programmes are in a unique position to work towards the end of gender-based violence. However, in order to promote safe perpetrator work, it is crucial to focus on the impact of IPV on the victims and survivors. In this context, little research has triangulated data by including both, victim’s perspectives on the impact that IPV has on them and also men’s level of awareness of the impact of their violent behaviour. In this paper, results from the “Impact Outcome Monitoring Toolkit (Impact Toolkit)” from one perpetrator treatment programme in the UK are presented. Participants were 98 in total; 49 men that were following treatment in a perpetrator program and their (ex-) partners. The differences in their perceptions of the IPV, but also on the impact of this abusive behavior on the victims, is described. Finally, recommendations for research and practice are discussed

Bures Metrics for Certain High-Dimensional Quantum Systems

Hubner's formula for the Bures (statistical distance) metric is applied to both a one-parameter and a two-parameter series (n=2,...,7) of sets of 2^n x 2^n density matrices. In the doubly-parameterized series, the sets are comprised of the n-fold tensor products --- corresponding to n independent, identical quantum systems --- of the 2 x 2 density matrices with real entries. The Gaussian curvatures of the corresponding Bures metrics are found to be constants (4/n). In the second series of 2^n x 2^n density matrices studied, the singly-parameterized sets are formed --- following a study of Krattenthaler and Slater --- by averaging with respect to a certain Gibbs distribution, the n-fold tensor products of the 2 x 2 density matrices with complex entries. For n = 100, we are also able to compute the Bures distance between two arbitrary (not necessarily neighboring) density matrices in this particular series, making use of the eigenvalue formulas of Krattenthaler and Slater, together with the knowledge that the 2^n x 2^n density matrices in this series commute.Comment: 8 pages, LaTeX, 4 postscript figures, minor changes, to appear in Physics Letters

Time-dependent restricted active space Configuration Interaction for the photoionization of many-electron atoms

We introduce the time-dependent restricted active space Configuration Interaction method to solve the time-dependent Schr\"odinger equation for many-electron atoms, and particularly apply it to the treatment of photoionization processes in atoms. The method is presented in a very general formulation and incorporates a wide range of commonly used approximation schemes, like the single-active electron approximation, time-dependent Configuration Interaction with single-excitations, or the time-dependent R-matrix method. We proof the applicability of the method by calculating the photoionization cross sections of Helium and Beryllium, as well as the X-ray--IR pump-probe ionization in BerylliumComment: 12 pages, 9 figure

Full Spin and Spatial Symmetry Adapted Technique for Correlated Electronic Hamiltonians: Application to an Icosahedral Cluster

One of the long standing problems in quantum chemistry had been the inability to exploit full spatial and spin symmetry of an electronic Hamiltonian belonging to a non-Abelian point group. Here we present a general technique which can utilize all the symmetries of an electronic (magnetic) Hamiltonian to obtain its full eigenvalue spectrum. This is a hybrid method based on Valence Bond basis and the basis of constant z-component of the total spin. This technique is applicable to systems with any point group symmetry and is easy to implement on a computer. We illustrate the power of the method by applying it to a model icosahedral half-filled electronic system. This model spans a huge Hilbert space (dimension 1,778,966) and in the largest non-Abelian point group. The $C_{60}$ molecule has this symmetry and hence our calculation throw light on the higher energy excited states of the bucky ball. This method can also be utilized to study finite temperature properties of strongly correlated systems within an exact diagonalization approach.Comment: 21 pages, 7 figures, abstract rewritten, a few changes in text, to appear in International Journal of Quantum Chemistr