Attractor Flows from Defect Lines

Deforming a two dimensional conformal field theory on one side of a trivial defect line gives rise to a defect separating the original theory from its deformation. The Casimir force between these defects and other defect lines or boundaries is used to construct flows on bulk moduli spaces of CFTs. It turns out, that these flows are constant reparametrizations of gradient flows of the g-functions of the chosen defect or boundary condition. The special flows associated to supersymmetric boundary conditions in N=(2,2) superconformal field theories agree with the attractor flows studied in the context of black holes in N=2 supergravity.Comment: 28 page

Topic Maps as a Virtual Observatory tool

One major component of the VO will be catalogs measuring gigabytes and terrabytes if not more. Some mechanism like XML will be used for structuring the information. However, such mechanisms are not good for information retrieval on their own. For retrieval we use queries. Topic Maps that have started becoming popular recently are excellent for segregating information that results from a query. A Topic Map is a structured network of hyperlinks above an information pool. Different Topic Maps can form different layers above the same information pool and provide us with different views of it. This facilitates in being able to ask exact questions, aiding us in looking for gold needles in the proverbial haystack. Here we discuss the specifics of what Topic Maps are and how they can be implemented within the VO framework. URL: http://www.astro.caltech.edu/~aam/science/topicmaps/Comment: 11 pages, 5 eps figures, to appear in SPIE Annual Meeting 2001 proceedings (Astronomical Data Analysis), uses spie.st

Chiral Supersymmetric Gepner Model Orientifolds

We explicitly construct A-type orientifolds of supersymmetric Gepner models. In order to reduce the tadpole cancellation conditions to a treatable number we explicitly work out the generic form of the one-loop Klein bottle, annulus and Moebius strip amplitudes for simple current extensions of Gepner models. Equipped with these formulas, we discuss two examples in detail to provide evidence that in this setting certain features of the MSSM like unitary gauge groups with large enough rank, chirality and family replication can be achieved.Comment: 37 pages, TeX (harvmac), minor changes, typos corrected, to appear in JHE

Postcard: Mushroom Rock, Thirty Feet High, Ellsworth, Kansas

This colorized photographic postcard features a large mushroom shaped rock at the Mushroom Rock State Park, an attraction in Ellsworth County, Kansas. A woman in a dress and hat stands to the right of the rock. Prairie land surrounds the rock. There is printed text on the front of the card and illegible handwriting. There is handwriting on the back of the card.https://scholars.fhsu.edu/tj_postcards/1325/thumbnail.jp

On neutrino oscillations searches with ANTARES

International audienceAlthough the first evidence for neutrino oscillations came from measurements on atmospheric neutrinos in underground experiments, neutrino oscillations have yet to be demonstrated in high energy neutrino telescopes, whose energy threshold is significantly higher. Recent studies have shown that a clean sample of atmospheric neutrinos with energies as low as 20GeV can be isolated in the ANTARES neutrino telescope. Such a threshold is low enough to allow the observation of neutrino oscillation features. A robust analysis method is presented which allows the extraction of atmospheric neutrino oscillation parameters