1,752 research outputs found

    Computer Monitoring: The Hidden War Of Control

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    Monitoring has become the battleground for control between labor and management.  A model is proposed which examines the dynamics of monitoring on labor through three functions.  The first is the use of computer monitoring to reduce the worker to simply another part of the whole machine.  The second function is to reduce workers to numbers arranged by their ability to meet mechanistic goals and objectives.  The third looks at the ability of monitoring to reduce costs beyond automation through its elimination of supervision and middle-management.  Implications are discussed

    Gluon Distribution Functions for Very Large Nuclei at Small Transverse Momentum

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    We show that the gluon distribution function for very large nuclei may be computed for small transverse momentum as correlation functions of an ultraviolet finite two dimensional Euclidean field theory. This computation is valid to all orders in the density of partons per unit area, but to lowest order in αs\alpha_s. The gluon distribution function is proportional to 1/x1/x, and the effect of the finite density of partons is to modify the dependence on transverse momentum for small transverse momentum.Comment: TPI--MINN--93--52/T, NUC--MINN--93--28/T, UMN--TH--1224/93, LaTex, 11 page

    Quantum state tomography with quantum shotnoise

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    We propose a scheme for a complete reconstruction of one- and two-particle orbital quantum states in mesoscopic conductors. The conductor in the transport state continuously emits orbital quantum states. The orbital states are manipulated by electronic beamsplitters and detected by measurements of average currents and zero frequency current shotnoise correlators. We show how, by a suitable complete set of measurements, the elements of the density matrices of the one- and two-particle states can be directly expressed in terms of the currents and current correlators.Comment: 4 pages, 2 figure

    Dilaton as a Dark Matter Candidate and its Detection

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    Assuming that the dilaton is the dark matter of the universe, we propose an experiment to detect the relic dilaton using the electromagnetic resonant cavity, based on the dilaton-photon conversion in strong electromagnetic background. We calculate the density of the relic dilaton, and estimate the dilaton mass for which the dilaton becomes the dark matter of the universe. With this we calculate the dilaton detection power in the resonant cavity, and compare it with the axion detection power in similar resonant cavity experiment.Comment: 23 pages, 2 figure

    The difference between Dirac's hole theory and quantum field theory

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    Dirac's hole theory and quantum field theory are generally thought to be equivalent. In fact field theory can be derived from hole theory through the process of second quantization. However, it can be shown that problems worked in both theories yield different results. The reason for the difference between the two theories will be examined and the effect the this difference has on the way calculations are done in quantum theory will be examined.Comment: Accepted as a chapter in "Progress in Quantum Physics Research" Nova Science Publishers. 62 page

    The locally covariant Dirac field

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    We describe the free Dirac field in a four dimensional spacetime as a locally covariant quantum field theory in the sense of Brunetti, Fredenhagen and Verch, using a representation independent construction. The freedom in the geometric constructions involved can be encoded in terms of the cohomology of the category of spin spacetimes. If we restrict ourselves to the observable algebra the cohomological obstructions vanish and the theory is unique. We establish some basic properties of the theory and discuss the class of Hadamard states, filling some technical gaps in the literature. Finally we show that the relative Cauchy evolution yields commutators with the stress-energy-momentum tensor, as in the scalar field case.Comment: 36 pages; v2 minor changes, typos corrected, updated references and acknowledgement

    Non-Perturbative Spectrum of Two Dimensional (1,1) Super Yang-Mills at Finite and Large N

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    We consider the dimensional reduction of N = 1 SYM_{2+1} to 1+1 dimensions, which has (1,1) supersymmetry. The gauge groups we consider are U(N) and SU(N), where N is a finite variable. We implement Discrete Light-Cone Quantization to determine non-perturbatively the bound states in this theory. A careful analysis of the spectrum is performed at various values of N, including the case where N is large (but finite), allowing a precise measurement of the 1/N effects in the quantum theory. The low energy sector of the theory is shown to be dominated by string-like states. The techniques developed here may be applied to any two dimensional field theory with or without supersymmetry.Comment: LaTex 18 pages; 5 Encapsulated PostScript figure

    Pairing of Parafermions of Order 2: Seniority Model

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    As generalizations of the fermion seniority model, four multi-mode Hamiltonians are considered to investigate some of the consequences of the pairing of parafermions of order two. 2-particle and 4-particle states are explicitly constructed for H_A = - G A^+ A with A^+}= 1/2 Sum c_{m}^+ c_{-m}^+ and the distinct H_C = - G C^+ C with C^+}= 1/2 Sum c_{-m}^+ c_{m}^+, and for the time-reversal invariant H_(-)= -G (A^+ - C^+)(A-C) and H_(+) = -G (A^+dagger + C^+)(A+C), which has no analogue in the fermion case. The spectra and degeneracies are compared with those of the usual fermion seniority model.Comment: 18 pages, no figures, no macro

    Optical Absorption Characteristics of Silicon Nanowires for Photovoltaic Applications

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    Solar cells have generated a lot of interest as a potential source of clean renewable energy for the future. However a big bottleneck in wide scale deployment of these energy sources remain the low efficiency of these conversion devices. Recently the use of nanostructures and the strategy of quantum confinement have been as a general approach towards better charge carrier generation and capture. In this article we have presented calculations on the optical characteristics of nanowires made out of Silicon. Our calculations show these nanowires form excellent optoelectronic materials and may yield efficient photovoltaic devices

    Van der Waals density functional: Self-consistent potential and the nature of the van der Waals bond

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    We derive the exchange-correlation potential corresponding to the nonlocal van der Waals density functional [M. Dion, H. Rydberg, E. Schroder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)]. We use this potential for a self-consistent calculation of the ground state properties of a number of van der Waals complexes as well as crystalline silicon. For the latter, where little or no van der Waals interaction is expected, we find that the results are mostly determined by semilocal exchange and correlation as in standard generalized gradient approximations (GGA), with the fully nonlocal term giving little effect. On the other hand, our results for the van der Waals complexes show that the self-consistency has little effect at equilibrium separations. This finding validates previous calculations with the same functional that treated the fully nonlocal term as a post GGA perturbation. A comparison of our results with wave-function calculations demonstrates the usefulness of our approach. The exchange-correlation potential also allows us to calculate Hellmann-Feynman forces, hence providing the means for efficient geometry relaxations as well as unleashing the potential use of other standard techniques that depend on the self-consistent charge distribution. The nature of the van der Waals bond is discussed in terms of the self-consistent bonding charge.Comment: submitted to Phys. Rev.
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