1,518 research outputs found
Detection of Asynchronous Message Passing Errors Using Static Analysis
Concurrent programming is hard and prone to subtle errors. In this paper we present a static analysis that is able to detect some commonly occurring kinds of message passing errors in languages with dynamic process creation and communication based on asynchronous message passing. Our analysis is completely automatic, fast, and strikes a proper balance between soundness and completeness: it is effective in detecting errors and avoids false alarms by computing a close approximation of the interprocess communication topology of programs. We have integrated our analysis in dialyzer, a widely used tool for detecting software defects in Erlang programs, and demonstrate its effectiveness on libraries and applications of considerable size. Despite the fact that these applications have been developed over a long period of time and are reasonably well-tested, our analysis has managed to detect a significant number of previously unknown message passing errors in their code
Orbits of quantum states and geometry of Bloch vectors for -level systems
Physical constraints such as positivity endow the set of quantum states with
a rich geometry if the system dimension is greater than two. To shed some light
on the complicated structure of the set of quantum states, we consider a
stratification with strata given by unitary orbit manifolds, which can be
identified with flag manifolds. The results are applied to study the geometry
of the coherence vector for n-level quantum systems. It is shown that the
unitary orbits can be naturally identified with spheres in R^{n^2-1} only for
n=2. In higher dimensions the coherence vector only defines a non-surjective
embedding into a closed ball. A detailed analysis of the three-level case is
presented. Finally, a refined stratification in terms of symplectic orbits is
considered.Comment: 15 pages LaTeX, 3 figures, reformatted, slightly modified version,
corrected eq.(3), to appear in J. Physics
The Trilinear Hamiltonian: A Zero Dimensional Model of Hawking Radiation from a Quantized Source
We investigate a quantum parametric amplifier with dynamical pump mode,
viewed as a zero-dimensional model of Hawking radiation from an evaporating
black hole. The conditions are derived under which the spectrum of particles
generated from vacuum fluctuations deviates from the thermal spectrum predicted
for the conventional parametric amplifier. We find that significant deviations
arise when the pump mode (black hole) has emitted nearly half of its initial
energy into the signal (Hawking radiation) and idler (in-falling particle)
modes. As a model of black hole dynamics, this finding lends support to the
view that late-time Hawking radiation contains information about the quantum
state of the black hole and is entangled with the black hole's quantum
gravitational degrees of freedom.Comment: 18 pages, 6 figures, Submitted to New Journal of Physics focus issue:
"Classical and Quantum Analogues for Gravitational Phenomena and Related
Effects
The male of the species: a profile of men in nursing
Aim: To establish a profile of men in nursing in Western Australia and explore the perception of men in nursing from the perspective of male and female nurses.
Background: A project team, including some of the current authors, produced a YouTube video and DVD about men in nursing which led to further inquiry on this topic.
Design: The study employed a non-experimental, comparative, descriptive research design focused on a quantitative methodology, using an online survey in early 2014.
Method: A convenience sample incorporated registered and enrolled nurses and midwives in Western Australia.
Findings: The range of data included demographic information and the respondentsâ perceptions of men in nursing were collected. Findings indicated that the main reasons for choosing a career in nursing or midwifery were similar for both genders. Common mis-perceptions of men in nursing included: most male nurses are gay; men are not suited to nursing and men are less caring and compassionate than women. Suggestions to promote nursing to men included: nurses are highly skilled professionals; there is the potential to make a difference for patients; nursing offers stable employment, professional diversity and opportunities for team work. There is a diminished awareness of opportunities for men in nursing and negative stereotypes related to men in nursing persist.
Conclusion: The study produced recommendations which included: using the right message to target the recruitment for men and promoting a more realistic understanding of the profile and perception of men in nursing
Whole-field 3D Characterization of a Pulsating Jet using Synthetic Aperture Particle Image Velocimety
In this study synthetic aperture particle image velocimetry is used on an excised human vocal fold model to study the airflow over the vocal folds during voice production. For the first time, a whole-field, time-resolved, 3D description of the flow is presented over one cycle of vocal fold oscillation. Complex, unsteady, 3D flow behavior is observed as the jet evolves
Entanglement, measurement, and conditional evolution of the Kondo singlet interacting with a mesoscopic detector
We investigate various aspects of the Kondo singlet in a quantum dot (QD)
electrostatically coupled to a mesoscopic detector. The two subsystems are
represented by an entangled state between the Kondo singlet and the
charge-dependent detector state. We show that the phase-coherence of the Kondo
singlet is destroyed in a way that is sensitive to the charge-state information
restored both in the magnitude and in the phase of the scattering coefficients
of the detector. We also introduce the notion of the `conditional evolution' of
the Kondo singlet under projective measurement on the detector. Our study
reveals that the state of the composite system is disentangled upon this
measurement. The Kondo singlet evolves into a particular state with a fixed
number of electrons in the quantum dot. Its relaxation time is shown to be
sensitive only to the QD-charge dependence of the transmission probability in
the detector, which implies that the phase information is erased in this
conditional evolution process. We discuss implications of our observations in
view of the possible experimental realization.Comment: Focus issue on "Interference in Mesoscopic Systems" of New J. Phy
Preanalytical processing of archaeological mammal enamel apatite carbonates for stable isotope investigations: a comparative analysis of the effect of acid treatment on samples from Northwest Australia
Stable isotopic analysis of palaeontological and archaeological biogenic apatite carbonates from herbivorous mammalian species represents an important tool for worldwide palaeoecological research. Tooth enamel carbonates are more resistant to taphonomic processes than bone or dentine carbonates but are not invulnerable to diagenesis. As such, they require careful preanalytical processing that considers depositional environment and age. An established part of this process includes a weak acid treatment to remove soluble exogenous carbonates; however, published treatment times for isotopic studies of archaeological tooth enamel are variable and range from 15\ua0min to over 8\ua0hr. This study tests three different pretreatment protocols on modern and Pleistocene age archaeological kangaroo teeth (dating from contemporary to 46,000 bp) to assess the effect of acid treatment time on isotopic integrity. The results indicate that treatment time is a critical parameter for producing consistency across results and shorter pretreatments of 4\ua0hr or less are preferable for removing diagenetic carbonates while minimising alteration of the biological signal
Long-range coupling and scalable architecture for superconducting flux qubits
Constructing a fault-tolerant quantum computer is a daunting task. Given any
design, it is possible to determine the maximum error rate of each type of
component that can be tolerated while still permitting arbitrarily large-scale
quantum computation. It is an underappreciated fact that including an
appropriately designed mechanism enabling long-range qubit coupling or
transport substantially increases the maximum tolerable error rates of all
components. With this thought in mind, we take the superconducting flux qubit
coupling mechanism described in PRB 70, 140501 (2004) and extend it to allow
approximately 500 MHz coupling of square flux qubits, 50 um a side, at a
distance of up to several mm. This mechanism is then used as the basis of two
scalable architectures for flux qubits taking into account crosstalk and
fault-tolerant considerations such as permitting a universal set of logical
gates, parallelism, measurement and initialization, and data mobility.Comment: 8 pages, 11 figure
Elementary Forms of the Metaphorical Life : Tropes at Work in Durkheimâs Theory of the Religious
Peer reviewedPostprin
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