711 research outputs found
Confined Maxwell Field and Temperature Inversion Symmetry
We evaluate the Casimir vacuum energy at finite temperature associated with
the Maxwell field confined by a perfectly conducting rectangular cavity and
show that an extended version of the temperature inversion symmetry is present
in this system
LeakWatch: Estimating Information Leakage from Java Programs
Abstract. Programs that process secret data may inadvertently reveal information about those secrets in their publicly-observable output. This paper presents LeakWatch, a quantitative information leakage analysis tool for the Java programming language; it is based on a flexible “point-to-point ” information leakage model, where secret and publiclyobservable data may occur at any time during a program’s execution. LeakWatch repeatedly executes a Java program containing both secret and publicly-observable data and uses robust statistical techniques to provide estimates, with confidence intervals, for min-entropy leakage (using a new theoretical result presented in this paper) and mutual information. We demonstrate how LeakWatch can be used to estimate the size of information leaks in a range of real-world Java programs
An exploration of concepts of community through a case study of UK university web production
The paper explores the inter-relation and differences between the concepts of occupational community, community of practice, online community and social network. It uses as a case study illustration the domain of UK university web site production and specifically a listserv for those involved in it. Different latent occupational communities are explored, and the potential for the listserv to help realize these as an active sense of community is considered. The listserv is not (for most participants) a tight knit community of practice, indeed it fails many criteria for an online community. It is perhaps best conceived as a loose knit network of practice, valued for information, implicit support and for the maintenance of weak ties. Through the analysis the case for using strict definitions of the theoretical concepts is made
Field Theoretical Quantum Effects on the Kerr Geometry
We study quantum aspects of the Einstein gravity with one time-like and one
space-like Killing vector commuting with each other. The theory is formulated
as a \coset nonlinear -model coupled to gravity. The quantum analysis
of the nonlinear -model part, which includes all the dynamical degrees
of freedom, can be carried out in a parallel way to ordinary nonlinear
-models in spite of the existence of an unusual coupling. This means
that we can investigate consistently the quantum properties of the Einstein
gravity, though we are limited to the fluctuations depending only on two
coordinates. We find the forms of the beta functions to all orders up to
numerical coefficients. Finally we consider the quantum effects of the
renormalization on the Kerr black hole as an example. It turns out that the
asymptotically flat region remains intact and stable, while, in a certain
approximation, it is shown that the inner geometry changes considerably however
small the quantum effects may be.Comment: 16 pages, LaTeX. The hep-th number added on the cover, and minor
typos correcte
The effect of higher derivative correction on and conductivities in STU model
In this paper we study the ratio of shear viscosity to entropy, electrical
and thermal conductivities for the R-charged black hole in STU model. We
generalize previous works to the case of a black hole with three different
charges. Actually we use diffusion constant to obtain ratio of shear viscosity
to entropy. By applying the thermodynamical stability we recover previous
results. Also we investigate the effect of higher derivative corrections.Comment: revised versio
Scheduler-Independent Declassification
Abstract The controlled declassification of secrets has received much attention in research on information-flow security, though mostly for se-quential programming languages. In this article, we aim at guarantee-ing the security of concurrent programs. We propose the novel security property WHAT&WHERE that allows one to limit what information may be declassified where in a program. We show that our property provides adequate security guarantees independent of the scheduling al-gorithm (which is non-trivial due to the refinement paradox) and present a security type system that reliably enforces the property. In a second scheduler-independence result, we show that an earlier proposed security condition is adequate for the same range of schedulers. These are the first scheduler-independence results in the presence of declassification.
Clean Time-Dependent String Backgrounds from Bubble Baths
We consider the set of controlled time-dependent backgrounds of general
relativity and string theory describing ``bubbles of nothing'', obtained via
double analytic continuation of black hole solutions. We analyze their quantum
stability, uncover some novel features of their dynamics, identify their causal
structure and observables, and compute their particle production spectrum. We
present a general relation between squeezed states, such as those arising in
cosmological particle creation, and nonlocal theories on the string worldsheet.
The bubble backgrounds have various aspects in common with de Sitter space,
Rindler space, and moving mirror systems, but constitute controlled solutions
of general relativity and string theory with no external forces. They provide a
useful theoretical laboratory for studying issues of observables in systems
with cosmological horizons, particle creation, and time-dependent string
perturbation theory.Comment: 38 pages, harvmac big, 6 figure
Quantum Radiation from a 5-Dimensional Rotating Black Hole
We study a massless scalar field propagating in the background of a
five-dimensional rotating black hole. We showed that in the Myers-Perry metric
describing such a black hole the massless field equation allows the separation
of variables. The obtained angular equation is a generalization of the equation
for spheroidal functions. The radial equation is similar to the radial
Teukolsky equation for the 4-dimensional Kerr metric. We use these results to
quantize the massless scalar field in the space-time of the 5-dimensional
rotating black hole and to derive expressions for energy and angular momentum
fluxes from such a black hole.Comment: references added, accepted for publication in Physical Review
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