470 research outputs found
Per Berglund Professor of Physics travels to Germany
The CIE grant provided financial support to travel in May 2013 to Hamburg, Germany to visit DESY, the German Electron Synchrotron, one of the world\u27s leading particle accelerators used to study the fundamental constituents of nature and their interactions. My local expenses were covered by a Collaborative Research Center (SFB) fellowship that I was awarded through SFBâs 676 Particle, Strings and the Early Universe--The Structure of Matter and Space-Time hosted by DESY and the University of Hamburg. Together these awards facilitated two months of visits and collaborations with theoretical physicists at DESY in 2013
Stringy corrections to Kahler potentials, SUSY breaking, and the cosmological constant problem
The moduli of N=1 compactifications of IIB string theory can be stabilized by
a combination of fluxes (which freeze complex structure moduli and the dilaton)
and nonperturbative superpotentials (which freeze Kahler moduli), typically
leading to supersymmetric AdS vacua. We show that stringy corrections to the
Kahler potential qualitatively alter the structure of the effective scalar
potential even at large volume, and can give rise to non-supersymmetric vacua
including metastable de Sitter spacetimes. Our results suggest an approach to
solving the cosmological constant problem, so that the scale of the 1-loop
corrected cosmological constant can be much smaller than the scale of
supersymmetry breaking.Comment: LaTeX, 2 EPS figures. If you use mpage on a Unix machine to print
multiple pages on a single sheet you may experience problems printing the
figures. v3: corrections and comments in cosmological constant sectio
Multi-Field Inflation from String Theory
We construct a multi-field inflationary model consisting of multiple K\"ahler
moduli derived from type IIB string compactification in the large volume limit.
The model consists of both heavy and light fields, with the former being frozen
during the inflationary period and the latter acting as the inflaton(s). We
study the evolution of all the fields during and after inflation until the
preheating era when all the fields oscillate around their vacuum expectation
values. Our numerical analysis shows that the curvature perturbations have an
almost scale invariant power spectrum with .Comment: 25 pages, 17 figure
Extent and Distribution of Urban Tax Delinquency
Purpose â Work-place learning takes place in many settings and in different ways, resulting in knowledge and skills of different kinds. The recognition process in the work place is however often implicit and seldom discussed in terms of recognition of prior learning (RPL). The aim of this paper is to give examples of how the knowledge/skills of employees get recognition in the workplace and to discuss what the consequences of such recognition processes might be. Design/methodology/approach â This paper is based on a study in two companies and two municipalities, where 21 interviews were conducted with human resource managers, team leaders and union representatives. The research questions concerned the ways skills were recognised among employees and how the logics of these actions could be understood. Findings â The findings show that both companies and municipalities have their own ways of assessing knowledge/skills, mostly out of a production logic of what is needed at the workplace. However, certain skills are also made âunvisualisedâ for the employee. This employer-controlled recognition logic is important to understand when RPL models are brought to the work place in order to obtain win-win situations for both employers and employees. Practical implications â It seems important to identify an already existing system for assessment of knowledge/skills at the workplace when bringing RPL processes to the workplace. Originality/value â The approach to understand assessment processes in these companies and municipalities from an RPL perspective has not been widely covered before
Non-Gaussianity in String Cosmology: A Case Study
We study non-gaussianity effects, using the formalism, in a
multi-field inflationary model consisting of K\"ahler moduli derived from type
IIB string compactification in the large volume limit. The analytical work in
this paper mostly follows the separable potential method developed by Vernizzi
and Wands. The numerical analysis is then used in computing non-gaussianity
beyond slow-roll regime. The possibility of the curvaton scenario is also
discussed. We give the condition for the existence of the curvaton and
calculate the non-guassianity generated by the curvaton decay in the large
volume limit.Comment: 25 page
Exploring transaminase stability for biocatalysis
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The AdS/CFT correspondence and Spectrum Generating Algebras
We list the spectrum generating algebras for string theory and M-theory
compactified on various backgrounds of the form . We
identify the representations of these algebras which make up the classical
supergravity spectra and argue for the presence of these spectrum generating
algebras in the classical string/M-theory. We also discuss the role of the
spectrum generating algebras on the conformal field theory side.Comment: 17 pages, 4 Tables, harvma
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