Reverse engineering in many-body quantum physics: Correspondence between many-body systems and effective single-particle equations

The mapping, exact or approximate, of a many-body problem onto an effective single-body problem is one of the most widely used conceptual and computational tools of physics. Here, we propose and investigate the inverse map of effective approximate single-particle equations onto the corresponding many-particle system. This approach allows us to understand which interacting system a given single-particle approximation is actually describing, and how far this is from the original physical many-body system. We illustrate the resulting reverse engineering process by means of the Kohn-Sham equations of density-functional theory. In this application, our procedure sheds light on the nonlocality of the density-potential mapping of density-functional theory, and on the self-interaction error inherent in approximate density functionals.

No association between the deficit syndrome in psychosis and summer birth in a Southern Hemisphere country (Correspondence)

This Article does not have an abstract.

Linear models of simple cells: Correspondence to real cell responses and space spanning properties

Despite their limitations, linear filter models continue to be used to simulate the receptive field properties of cortical simple cells. For theoreticians interested in large scale models of visual cortex, a family of self-similar filters represents a convenient way in which to characterise simple cells in one basic model. This paper reviews research on the suitability of such models, and goes on to advance biologically motivated reasons for adopting a particular group of models in preference to all others. In particular, the paper describes why the Gabor model, so often used in network simulations, should be dropped in favour of a Cauchy model, both on the grounds of frequency response and mutual filter orthogonality.

Improving attitude-behavior correspondence through exposure to normative support from a salient ingroup

Two experiments were conducted to test predictions derived from social identity/self-categorization theory concerning the role of group norms in attitude-behavior consistency. In Experiment 1, 160 students who could be classified as having a more or less certain target attitude were exposed to attitude congruent versus incongruent normative support from a relevant reference group (own university) under conditions of low versus high group salience. Experiment 2 was very similar in design and methodology (N=180), but a different correlate of attitude accessibility was used (an experimental manipulation of repeated expression), the target attitude was changed, and the reference group was gender. Across the 2 experiments there was consistent support for the hypothesis that participants would behave more in accordance with their attitudes when they received normative support for, rather than opposition to, their original attitude from a relevant reference group (i.e., their ingroup, not an outgroup). There was slightly weaker support for the second hypothesis that this effect would be stronger under high-than low-salience conditions. The third hypothesis (see Fazio, 1986), that attitude certainty and repeated expression of the attitude would strengthen attitude-behavior consistency, was well supported, as was the expectation that accessibility effects would be independent of reference group norm effects on attitude-behavior consistency.

Proceedings of the Committee of Science and Correspondence of the Zoological Society of London.

pt.1-2 (1830-1832)

Louis Agassiz; his life and correspondence, ed. by Elizabeth Cary Agassiz.

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Louis Agassiz; his life and correspondence, ed. by Elizabeth Cary Agassiz.

2

Ray-wave correspondence and extended ray dynamics in optical microcavities

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2011