21,476 research outputs found
A Relation Between N=8 Gauge Theories in Three Dimensions
We show that three-dimensional N=8 and gauge theories flow
to the same strong coupling fixed point. As a consequence, the corresponding
orientifold two-planes in type IIA string theory are described at strong
coupling and low-energies by the same M theory background. In the large
limit, these assertions are confirmed by studying discrete torsion in the
supergravity theory corresponding to membranes on .Comment: 8 pages, harvmac; an acknowledgement adde
The promotion of data sharing in pharmacoepidemiology
This article addresses the role of pharmacoepidemiology in patient safety and the crucial role of data sharing in ensuring that such activities occur. Against the backdrop of proposed reforms of European data protection legislation, it considers whether the current legislative landscape adequately facilitates this essential data sharing. It is argued that rather than maximising and promoting the benefits of such activities by facilitating data sharing, current and proposed legislative landscapes hamper these vital activities. The article posits that current and proposed data protection approaches to pharmacoepidemiology — and more broadly, re-uses of data — should be reoriented towards enabling these important safety enhancing activities. Two potential solutions are offered: 1) a dedicated working party on data reuse for health research and 2) the introduction of new, dedicated legislation
Supersymmetry Breaking by Fluxes
Type II string theory and M-theory admit flux configurations that break
supersymmetry below the Kaluza-Klein scale. These backgrounds play a central
role in most models of the string landscape. I argue that the behavior of such
backgrounds at weak coupling is generically a rolling solution, not a static
space-time. Quantum corrections to the space-time potential are computed around
this classical time-dependent background. This is particularly important for
non-perturbative corrections. This change in perspective offers an explanation
for why there appear to be many effective field theory models that seemingly
evade the known no-go theorems forbidding de Sitter space-times. This has
interesting implications for type IIB string landscape models.Comment: 31 pages; LaTeX; references added; minor changes and more references
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Stability of Equilibria in Games with Procedurally Rational Players
One approach to the modeling of bounded rationality in strategic environments is based on the dynamics of evolution and learning in games. An entirely different approach has been developed recently by Osborne and Rubinstein (1998). This latter approach is static and equilibrium based, but relies on less stringent assumptions regarding the knowledge and understanding of players than does the standard theory of Nash equilibrium. This paper formalizes Osborne and Rubinstein's dynamic interpretation of their equilibrium concept and thereby facilitates a comparison of this approach with the explicitly dynamic approach of evolutionary game theory. It turns out that the two approaches give rise to radically different static and dynamic predictions. For instance, dynamically stable equilibria can involve the playing of strictly dominated actions, and equilibria in which strictly actions are played with probability 1 can be unstable. Sufficient conditions for the instability of equilibria are provided for symmetric and asymmetric games.Dynamic Stability, S(1) Equilibrium, Procedural Rationality, Evolutionary Games
Domain Walls, Triples and Acceleration
We present a construction of domain walls in string theory. The domain walls
can bridge both Minkowski and AdS string vacua. A key ingredient in the
construction are novel classical Yang-Mills configurations, including
instantons, which interpolate between toroidal Yang-Mills vacua. Our
construction provides a concrete framework for the study of inflating metrics
in string theory. In some cases, the accelerating space-time comes with a
holographic description. The general form of the holographic dual is a field
theory with parameters that vary over space-time.Comment: 63 pages, 1 figure; LaTe
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