14,276 research outputs found
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
Experimental semi-device-independent certification of entangled measurements
Certifying the entanglement of quantum states with Bell inequalities allows
one to guarantee the security of quantum information protocols independently of
imperfections in the measuring devices. Here we present a similar procedure for
witnessing entangled measurements, which play a central role in many quantum
information tasks. Our procedure is termed semi-device-independent, as it uses
uncharacterized quantum preparations of fixed Hilbert space dimension. Using a
photonic setup, we experimentally certify an entangled measurement using
measurement statistics only. We also apply our techniques to certify
unentangled but nevertheless inherently quantum measurements.Comment: 7 pages, 2 figure
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
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