11,656 research outputs found
M-theory curves from warped AdS in Type IIB
We establish a close relation between recently constructed AdS solutions
in Type IIB supergravity, which describe the near-horizon limit of
5-brane junctions, and the curves wrapped by M5-branes in the M-theory
realization of the 5-brane junctions. This provides a geometric interpretation
of various objects appearing in the construction of the Type IIB solutions and
a physical interpretation of the regularity conditions. Conversely, the Type
IIB solutions provide explicit solutions to the equations defining the M-theory
curves associated with 5-brane junctions.Comment: 24 page
Evaluating the SiteStory Transactional Web Archive With the ApacheBench Tool
Conventional Web archives are created by periodically crawling a web site and
archiving the responses from the Web server. Although easy to implement and
common deployed, this form of archiving typically misses updates and may not be
suitable for all preservation scenarios, for example a site that is required
(perhaps for records compliance) to keep a copy of all pages it has served. In
contrast, transactional archives work in conjunction with a Web server to
record all pages that have been served. Los Alamos National Laboratory has
developed SiteSory, an open-source transactional archive written in Java
solution that runs on Apache Web servers, provides a Memento compatible access
interface, and WARC file export features. We used the ApacheBench utility on a
pre-release version of to measure response time and content delivery time in
different environments and on different machines. The performance tests were
designed to determine the feasibility of SiteStory as a production-level
solution for high fidelity automatic Web archiving. We found that SiteStory
does not significantly affect content server performance when it is performing
transactional archiving. Content server performance slows from 0.076 seconds to
0.086 seconds per Web page access when the content server is under load, and
from 0.15 seconds to 0.21 seconds when the resource has many embedded and
changing resources.Comment: 13 pages, Technical Repor
C-metrics in Gauged STU Supergravity and Beyond
We construct charged generalizations of the dilaton C-metric in various
four-dimensional theories, including STU gauged supergravity as well as a
one-parameter family of Einstein-Maxwell-dilaton theories whose scalar
potential can be expressed in terms of a superpotential. In addition, we
present time-dependent generalizations of the dilaton C-metric and dilaton
Ernst solutions, for which the time evolution is driven by the dilaton. These
C-metric solutions provide holographic descriptions of a strongly-coupled
three-dimensional field theory on the background of a black hole, a
gravitational soliton, and a black hole undergoing time evolution.Comment: 26 pages, comments and references adde
Warped Resolved L^{a,b,c} Cones
We construct supergravity solutions describing a stack of D3-branes localized
at a point on a blown-up cycle of a resolved L^{a,b,c} cone. The geometry flows
from AdS_5 x L^{a,b,c} to AdS_5 x S^5/Z_k. The corresponding quiver gauge
theory undergoes an RG flow between two superconformal fixed points, which
leads to semi-infinite chains of flows between the various L^{a,b,c} fixed
points. The general system is described by a triplet of Heun equations which
can each be solved by an expansion with a three-term recursion relation, though
there are closed-form solutions for certain cases. This enables us to read off
the operators which acquire non-zero vacuum expectation values as the quiver
gauge theory flows away from a fixed point.Comment: 28 pages, 4 figures, additional reference
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