6,526 research outputs found

    Report of conference evaluation committee

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    A general classification is made of a number of approaches used for the prediction of turbulent shear flows. The sensitivity of these prediction methods to parameter values and initial data are discussed in terms of variable density, pressure fluctuation, gradient diffusion, low Reynolds number, and influence of geometry

    Equilibrium and Disorder-induced behavior in Quantum Light-Matter Systems

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    We analyze equilibrium properties of coupled-doped cavities described by the Jaynes-Cummings- Hubbard Hamiltonian. In particular, we characterize the entanglement of the system in relation to the insulating-superfluid phase transition. We point out the existence of a crossover inside the superfluid phase of the system when the excitations change from polaritonic to purely photonic. Using an ensemble statistical approach for small systems and stochastic-mean-field theory for large systems we analyze static disorder of the characteristic parameters of the system and explore the ground state induced statistics. We report on a variety of glassy phases deriving from the hybrid statistics of the system. On-site strong disorder induces insulating behavior through two different mechanisms. For disorder in the light-matter detuning, low energy cavities dominate the statistics allowing the excitations to localize and bunch in such cavities. In the case of disorder in the light- matter coupling, sites with strong coupling between light and matter become very significant, which enhances the Mott-like insulating behavior. Inter-site (hopping) disorder induces fluidity and the dominant sites are strongly coupled to each other.Comment: about 10 pages, 12 figure

    Magnetic Hole Formation from the Perspective of Inverse Scattering Theory

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    The dynamics of oblique, weakly dispersive nonlinear Alfven waves in the presence of weak resistive damping are investigated numerically through an extension of the derivative nonlinear Schrodinger (DNLS) equation. It is observed numerically that the nonlinear dynamics are organized around the dynamics and allowed interactions of the underlying DNLS soliton families. There are three types of oblique Alfven solitons: the compressive two-parameter soliton and one-parameter bright soliton along with the rare factive one-parameter dark soliton. The damping of either of these compressive solitons is accompanied by the formation of one or more dark solitons. The implication of these processes is that any initial wave profile containing solitons in its Inverse Scattering Transformation representation, in the presence of weak resistive damping, will result in a leading train of dark solitons. These dark soliton shave been identified with magnetic holes, and the results described above are discussed in the context of magnetic hole observations and theory

    Bell-inequality test of spatial mode entanglement of a single massive particle

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    Experiments showing the violation of Bell inequalities have formed our belief that the world at its smallest is genuinely non-local. While many non-locality experiments use the first quantised picture, the physics of fields of indistinguishable particles, such as bosonic gases, is captured most conveniently by second quantisation. This implies the possibility of non-local correlations, such as entanglement, between modes of the field. In this paper we propose an experimental scheme that tests the theoretically predicted entanglement between modes in space occupied by massive bosons. Moreover, the implementation of the proposed scheme is capable of proving that the particle number superselection rule is not a fundamental necessity of quantum theory but a consequence of not possessing a distinguished reference frame.Comment: 5 pages, 2 figures. Version two has been accepted for publication in Physical Review

    Rights or containment? The politics of Aboriginal cultural heritage in Victoria

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    Aboriginal cultural heritage protection, and the legislative regimes that underpin it, constitute important mechanisms for Aboriginal people to assert their rights and responsibilities. This is especially so in Victoria, where legislation vests wide-ranging powers and control of cultural heritage with Aboriginal communities. However, the politics of cultural heritage, including its institutionalisation as a scientific body of knowledge within the state, can also result in a powerful limiting of Aboriginal rights and responsibilities. This paper examines the politics of cultural heritage through a case study of a small forest in north-west Victoria. Here, a dispute about logging has pivoted around differing conceptualisations of Aboriginal cultural heritage values and their management. Cultural heritage, in this case, is both a powerful tool for the assertion of Aboriginal rights and interests, but simultaneously a set of boundaries within which the state operates to limit and manage the challenge those assertions pose. The paper will argue that Aboriginal cultural heritage is a politically contested and shifting domain structured around Aboriginal law and politics, Australian statute and the legacy of colonial history

    Coefficient Functions and Open Charm Production in Deep Inelastic Scattering

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    It is shown that the problem of double counting in open charm production in DIS can be solved by using the expression for DIS coefficient functions in terms of 2PI diagramsComment: 11 pages, REVTeX, no figure

    Extreme nonlocality with one photon

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    Quantum nonlocality is typically assigned to systems of two or more well separated particles, but nonlocality can also exist in systems consisting of just a single particle, when one considers the subsystems to be distant spatial field modes. Single particle nonlocality has been confirmed experimentally via a bipartite Bell inequality. In this paper, we introduce an N-party Hardy-like proof of impossibility of local elements of reality and a Bell inequality for local realistic theories for a single particle superposed symmetrical over N spatial field modes (i.e. a N qubit W state). We show that, in the limit of large N, the Hardy-like proof effectively becomes an all-versus nothing (or GHZ-like) proof, and the quantum-classical gap of the Bell inequality tends to be same of the one in a three-particle GHZ experiment. We detail how to test the nonlocality in realistic systems.Comment: 11 single column pages, 2 figures; v3 now includes a Bell inequality in addition to the results in the previous versio

    Three-dimensional flux states as a model for the pseudogap phase of transition metal oxides

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    We propose that the pseudogap state observed in the transition metal oxides can be explained by a three-dimensional flux state, which exhibits spontaneously generated currents in its ground state due to electron-electron correlations. We compare the energy of the flux state to other classes of mean field states, and find that it is stabilized over a wide range of tt and δ\delta. The signature of the state will be peaks in the neutron diffraction spectra, the location and intensity of which are presented. The dependence of the pseudogap in the optical conductivity is calculated based on the parameters in the model.Comment: submitted to Phys. Rev. B on January 8, 200

    Towards a global analysis of polarized parton distributions

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    We present a technique for implementing in a fast way, and without any approximations, higher-order calculations of partonic cross sections into global analyses of parton distribution functions. The approach, which is set up in Mellin-moment space, is particularly suited for analyses of future data from polarized proton-proton collisions, but not limited to this case. The usefulness and practicability of this method is demonstrated for the semi-inclusive production of hadrons in deep-inelastic scattering and the transverse momentum distribution of ``prompt'' photons in pp collisions, and a case study for a future global analysis of polarized parton densities is presented.Comment: 20 pages, LaTeX, 6 eps figures, final version to appear in PRD (minor changes

    Utility of Two iPhone Device Apps in Assessing Heart Rate at Rest and During Activity

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    Heart rate (HR) is a critical physiological variable used for prescribing exercise, assessing fitness level and tracking fitness improvements. Electrocardiography (ECG) stands as the criterion measure of HR. While recent development of HR-detecting mobile device applications (apps) has made evaluating HR more convenient; their degree of accuracy is unknown. Therefore, the purpose of this current study was to examine the accuracy and reliability of two-iPhone applications to detect HR at rest and during low-intensity exercise conditions. Eighteen female and 22 male subjects (26 + 9.5 yrs) were prepped for simultaneous detection of HR via three methods: ECG and two HR-detecting apps. App 1, a camera-based app called Azumio Instant Heart Rate (CAM), was used by placement of a finger over the camera lens of the mobile device. App 2, a microphone-based app called Heart Monitor by Bluespark, was employed via placement of an external microphone over the radial pulse. The participants underwent a series of 5-minute stages: seated rest followed by cycle then treadmill walking at low intensities. HR was recorded concurrently, at several time intervals from the three methods once a steady-state HR was reached. The means of the three devices were compared via ANOVA with the significance level set, a priori, at 0.05. Correlation analysis was employed to investigate relationships between the apps and ECG. No statistical difference was found between the CAM and ECG HR (p \u3e 0.05) during the resting and cycle stages. However, during the treadmill phase, there was a significant difference (p = 0.018) between CAM and ECG. Nevertheless, there was a significant (p \u3c 0.05), positive correlation between CAM and ECG under the resting, cycle and treadmill conditions (r = .966, r = .984, r = .877, respectively). Significant differences (p \u3c 0.05) were found for each condition when comparing ECG and MIC HR. Data also revealed poor correlations (p \u3e 0.05; r between -.004 and -.136) between MIC and ECG. The utility of CAM and MIC-based apps to detect HR remains in question as evidence appears to indicate exercise mode and app specificity. Caution should be shown when using these devices. The CAM-based app may accurately detect HR during resting and seated cycling but not during treadmill activity. The MIC-based app is not recommended for use in any condition. Of note, statistical significance may not mitigate usefulness when considering the accuracy of palpation. Additional research is necessary
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