1,720,979 research outputs found
The crossover between liquid and solid electron phases in quantumdots: A large-scale configuration-interaction study
No full textWe study the crossover between liquid and solid electron phases in a two-dimensional harmonic trap as the density is progressivelydiluted. We infer the formation of geometrically ordered phases from charge distributions and pair correlation functionsobtained via a large scale configuration interaction calculation
Reduced electron relaxation rate in multi-electron quantum dots
Full text linkWe use a configuration-interaction approach and the Fermi golden rule to investigate electron-phonon interaction in multielectron quantum dots. Lifetimes are computed in the low-density, highly correlated regime. We report numerical evidence that electron-electron interaction generally leads to reduced decay rates of excited electronic states in weakly confined quantum dots, where carrier relaxation is dominated by the interaction with longitudinal acoustic phonons
Coulomb Correlation in the Addition Spectra of Single and Coupled Quantum Dots
No full textQuantum dot
Single-electron charging in quantum dots with large dielectric mismatch
No full textSemiconductor quantum dots characterized by a strong dielectric mismatch with their environment arestudied theoretically through direct diagonalization of the many-body Hamiltonian. The enhancement of theelectron-electron Coulomb interaction, arising from polarization effects, is found to induce a strong increase inaddition energies with increasing dielectric mismatch. For large dielectric mismatch, the excited many-bodystates can undergo reconstructions as the dot is filled with carriers even in the absence of external magneticfields
Theory of addition spectra in double quantum dots: Single-particle tunneling vs Coulomb interactions
No full textWe study coupled semiconductor quantum dots theoretically using a generalized Hubbard approach, where intra- and inter-dot Coulomb correlation, as well as tunneling effects are described on the basis of realistic electron wavefunctions. We find that the ground-state configuration of vertically coupled double dots undergoes non-trivial quantum transitions as the inter-dot distance d changes; at intermediate values of d we predict a new phase that should be observable in the addition spectra and in the magnetization changes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
On-site correlations in narrow band materials
No full textWe present the results of a recently developed approach where the interplay between the itinerant and localized character of electrons in narrow band materials is described by adding on-site correlations to a realistic band calculatio
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