1,752 research outputs found
Computer Monitoring: The Hidden War Of Control
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
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 . The gluon distribution function is proportional to ,
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
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
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
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
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
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
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
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
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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