58,836 research outputs found
On the Kinetic Roughening in Polymer Film Growth by Vapor Deposition
This is a Comment on a recent publication: Y.-P. Zhao et al., Phys. Rev.
Lett. 85, 3229 (2000). In the Letter, the authors report on an experimental
investigation of polymeric (p-xylene) thin film growth and propose a new
universality class not previously known. Here, we point out that the critical
exponents reported in the Letter are consistent with the critical exponents of
Das Sarma-Tamborenea growth model.Comment: 2 pages, 1 figure include
Vertical diversity and equilbrium growth
This paper examines the effect of an increase in vertical diversity in workers' skill on the long run growth rate of an economy. It uses a two-secror model where the techonology of the consumption-good sector is supermodular and that of the R&D sector is submodular. By adopting Grossman and Maggi's(2000) model to a framework of growth based on R&D, it shows first that diversity is condutive to growth. As the main innovation, communication gap is introduced among workers. It is then shown that growth may not be increasing with diversity. There may be an inverse-U shaped relationship.Diversity, talent distribution, supermodular technology, submodular technology, growth, skill, R&D, innovations
Three Brane Action and The Correspondence Between N=4 Yang Mills Theory and Anti De Sitter Space
Recently, a relation between N=4 Super Yang Mills in 3+1 dimensions and
supergravity in an background has been proposed. In this paper we
explore the idea that the correspondence between operators in the Yang Mills
theory and modes of the supergravity theory can be obtained by using the D3
brane action. Specifically, we consider two form gauge fields for this purpose.
The supergravity analysis predicts that the operator which corresponds to this
mode has dimension six. We show that this is indeed the leading operator in the
three brane Dirac-Born-Infeld and Wess-Zumino action which couples to this
mode. It is important in the analysis that the brane action is expanded around
the anti de-Sitter background. Also, the Wess-Zumino term plays a crucial role
in cancelling a lower dimension operator which appears in the the
Dirac-Born-Infeld action.Comment: 12 pages, LaTex, no figures; error in the form of the final dimension
six operator corrected, some references and comments added, main conclusions
unchange
- …