arXiv subjects

Charles Jego

Publications and source records attributed to Charles Jego.

4 recordsLinked to original sources

arXiv2007

A physicist's view of the notion of "racism"

It is not uncommon, e.g. in the media, that specific groups are categorized as being racist. Based on an extensive dataset of intermarriage statistics our study questions the legitimacy of such characterizations. It suggests that, far from being group-dependent, segregation mechanisms are instead situation-dependent. More precisely, the degree of integration of a minority in terms of the frequency of intermarriage is seen to crucially depend upon the the proportion p of the minority. Thus, a population may have a segregative behavior with respect to a high-p (p>20%) minority A and at the same time a tolerant attitude toward a low-p (p<2%) minority B. This remains true even when A and B represent the same minority; for instance Black-White intermarriage is much more frequent in Montana than it is in South Carolina. In short, the nature of minority groups is largely irrelevant, the key factor being their proportion in a given area.

physics.soc-ph↗

arXiv2006

Open strings in Lie groups and associative products

Firstly, we generalize a semi-classical limit of open strings on D-branes in group manifolds. The limit gives rise to rigid open strings, whose dynamics can efficiently be described in terms of a matrix algebra. Alternatively, the dynamics is coded in group theory coefficients whose properties are translated in a diagrammatical language. In the case of compact groups, it is a simplified version of rational boundary conformal field theories, while for non-compact groups, the construction gives rise to new associative products. Secondly, we argue that the intuitive formalism that we provide for the semi-classical limit, extends to the case of quantum groups. The associative product we construct in this way is directly related to the boundary vertex operator algebra of open strings on symmetry preserving branes in WZW models, and generalizations thereof, e.g. to non-compact groups. We treat the groups SU(2) and SL(2,R) explicitly. We also discuss the precise relation of the semi-classical open string dynamics to Berezin quantization and to star product theory.

hep-th↗

arXiv2006

Notes on the Verlinde formula in non-rational conformal field theories

We review and extend evidence for the validity of a generalized Verlinde formula in particular non-rational conformal field theories. We identify a subset of representations of the chiral algebra in non-rational conformal field theories that give rise to an analogue of the relation between modular S-matrices and fusion coefficients in rational conformal field theories. To that end we review and extend the Cardy-type brane calculations in bosonic and supersymmetric Liouville theory (and its duals) as well as in the hyperbolic three-plane H3+. We analyze the three-point functions of Liouville theory and of H3+ in detail to directly identify the fusion coefficients from the operator product expansion.

hep-th↗

arXiv2006

White flight or flight from poverty?

The phenomenon of White flight is often illustrated by the case of Detroit whose population dropped from 1.80 million to 0.95 million between 1950 and 2000 while at the same time its Black and Hispanic component grew from 30 percent to 85 percent. But is this case really representative? The present paper shows that the phenomenon of White flight is in fact essentially a flight from poverty. As a confirmation, we show that the changes in White or Black populations are highly correlated which means that White flight is always paralleled by Black flight (and Hispanic flight as well). This broader interpretation of White flight accounts not only for the case of northern cities such as Cincinnati, Cleveland or Detroit, but for all population changes at county level, provided the population density is higher than a threshold of about 50 per square-kilometer which corresponds to moderately urbanized areas (as can be found in states like Indiana or Virginia for instance).

physics.soc-ph↗