1,289 research outputs found
Front Form Spinors in Weinberg-Soper Formalism and Melosh Transformations for any Spin
Using the Weinberg-Soper formalism we construct the front form
spinors. Explicit expressions for the generalised Melosh
transformations up to spin two are obtained. The formalism, without explicitly
invoking any wave equations, reproduces spin one half front-form results of
Melosh, Lepage and Brodsky, and Dziembowski.Comment: 16 Pages, RevTex. We continue to receive reprint requests for this
paper. So we now archive it her
On Quantum Nature of Black-Hole Spacetime: A Possible New Source of Intense Radiation
Atoms and the planets acquire their stability from the quantum mechanical
incompatibility of the position and momentum measurements. This incompatibility
is expressed by the fundamental commutator [x, p_x]=i hbar, or equivalently,
via the Heisenberg's uncertainty principle Delta x Delta p_x sim hbar. A
further stability-related phenomenon where the quantum realm plays a dramatic
role is the collapse of certain stars into white dwarfs and neutron stars.
Here, an intervention of the Pauli exclusion principle, via the fermionic
degenerate pressure, stops the gravitational collapse. However, by the
neutron-star stage the standard quantum realm runs dry. One is left with the
problematic collapse of a black hole. This essay is devoted to a concrete
argument on why the black-hole spacetime itself should exhibit a quantum
nature. The proposed quantum aspect of spacetime is shown to prevent the
general-relativistic dictated problematic collapse. The quantum nature of
black-hole spacetime is deciphered from a recent result on the universal
equal-area spacing [=lambda_P^2 4 ln(3)] for black holes. In one interpretation
of the emergent picture, an astrophysical black hole can fluctuate to
sqrt{pi/ln(3)} approx 1.7 times its classical size, and thus allow radiation
and matter to escape to the outside observers. These fluctuations I conjecture
provide a new source, perhaps beyond Hawking radiation, of intense radiation
from astrophysical black holes and may be the primary source of observed
radiation from those galactic cores what carry black hole(s). The presented
interpretation may be used as a criterion to choose black holes from black hole
candidates.Comment: This essay received an "honorable mention" in the 1999 Essay
Competition of the Gravity Research Foundation - Ed. Int. J. Mod. Phys. D
(1999, in press). For Joseph Knech
Understanding Country Level Adoption of E-Commerce: A Theoretical Model Including Technological, Institutional, and Cultural Factors
This paper provides a theoretically grounded model of e-commerce adoption to explain differences in adoption rates among countries. The model extends the existing culture-policy-technology (CPT) framework to examine causal relationships between the technological, institutional, and cultural factors in order to examine country-level e-commerce adoption. Thus, interesting relationships among macro-level factors are hypothesized. The paper highlights the important of risk mitigating mechanisms or institutions to facilitate adoption of e-commerce in countries with high uncertainty avoidance. A call for empirical examination into country level adoption is answered by analyzing macro level data from 69 countries. The hypotheses are confirmed using PLS analytical procedures. The study is timely as e-commerce technology has now taken hold in several countries but its revenues in proportion to the overall total revenues remain low. The study is motivated by significant different in e-commerce adoption rates among countries. The paper makes significant contributions to literature and practice
Information Security Policies Compliance: The Role of Organizational Punishment
It has been argued that organizational punishment serves as a deterrent to unwanted employee behavior but there is no clear consensus on the influence of punitive actions on employeesâ behavior to comply with information security policies. This study proposes a model that explains the influence of organizational punishment on employeesâ cognitive beliefs and their intention to comply with information security policies. We argue that likelihood of punishment impacts employeesâ cognitive beliefs that in turn affect their information security compliance behavior. This study uses the theory of planned behavior as a support for its propositions and contributes to the body of knowledge in the IS security stream by addressing a significant gap in the current literature. This is a work in progress and we plan to present results of the empirical study at the conference
L/E-Flatness of the Electron-Like Event Ratio in Super-Kamiokande and a Degeneracy in Neutrino Masses
We show that the L/E-flatness of the electron-like event ratio in the
Super-Kamiokande atmospheric neutrino data implies the equality of the
expectation values for the muon and tau neutrino masses. We establish this
result by obtaining a set of three constraints on the neutrino-oscillation
mixing matrix as contained in the indicated flatness. The resulting 3x3
neutrino-oscillation matrix depends only on one angle. A remarkable result that
follows directly from this matrix is the consistency between the mixing angles
observed by LSND and Super-Kamiokande.Comment: Journal versio
Exotic Low Density Fermion States in the Two Measures Field Theory: Neutrino Dark Energy
We study a new field theory effect in the cosmological context in the Two
Measures Field Theory (TMT). TMT is an alternative gravity and matter field
theory where the gravitational interaction of fermionic matter is reduced to
that of General Relativity when the energy density of the fermion matter is
much larger than the dark energy density. In this case also the 5-th force
problem is solved automatically. In the opposite limit, where the magnitudes of
fermionic energy density and scalar field dark energy density become
comparable, nonrelativistic fermions can participate in the cosmological
expansion in a very unusual manner. Some of the features of such states in a
toy model of the late time universe filled with homogeneous scalar field and
uniformly distributed nonrelativistic neutrinos: neutrino mass increases as m ~
a^{3/2}; the neutrino gas equation-of-state approaches w=-1, i.e. neutrinos
behave as a sort of dark energy; the total (scalar field + neutrino)
equation-of-state also approaches w=-1; the total energy density of such
universe is less than it would be in the universe filled with the scalar field
alone. An analytic solution is presented. A domain structure of the dark energy
seems to be possible. We speculate that decays of the CLEP state neutrinos may
be both an origin of cosmic rays and responsible for a late super-acceleration
of the universe. In this sense the CLEP states exhibit simultaneously new
physics at very low densities and for very high particle masses.Comment: 47 pages, accepted for publication in Int.J.Mod.Phys.
Viscoelastic Properties of Dynamically Asymmetric Binary Fluids Under Shear Flow
We study theoretically the viscoelastic properties of sheared binary fluids
that have strong dynamical asymmetry between the two components. The dynamical
asymmetry arises due to asymmetry between the viscoelastic stresses,
particularly the bulk stress. Our calculations are based on the two-fluid model
that incorporates the asymmetric stress distribution. We simulate the phase
separation process under an externally imposed shear and compare the asymmetric
case with the usual phase separation under a shear flow without viscoelastic
effects. We also simulate the behavior of phase separated stable morphologies
under applied shear and compute the stress relaxation.Comment: 10 pages text, 9 figure
On-chip TIRF nanoscopy by applying Haar wavelet kernel analysis on intensity fluctuations induced by chip illumination
Photonic-chip based TIRF illumination has been used to demonstrate several
on-chip optical nanoscopy methods. The sample is illuminated by the evanescent
field generated by the electromagnetic wave modes guided inside the optical
waveguide. In addition to the photokinetics of the fluorophores, the waveguide
modes can be further exploited for introducing controlled intensity
fluctuations for exploitation by techniques such as super-resolution optical
fluctuation imaging (SOFI). However, the problem of non-uniform illumination
pattern generated by the modes contribute to artifacts in the reconstructed
image. To alleviate this problem, we propose to perform Haar wavelet kernel
(HAWK) analysis on the original image stack prior to the application of (SOFI).
HAWK produces a computational image stack with higher spatio-temporal sparsity
than the original stack. In the case of multimoded non-uniform illumination
patterns, HAWK processing bre aks the mode pattern while introducing
spatio-temporal sparsity, thereby differentially affecting the non-uniformity
of the illumination. Consequently, this assists nanoscopy methods such as SOFI
to better support super-resolution, which is otherwise compromised due to
spatial correlation of the mode patterns in the raw image. Furthermore,
applying HAWK prior to SOFI alleviates the problem of artifacts due to
non-uniform illumination without degrading temporal resolution. Our
experimental results demonstrate resolution enhancement as well as reduction in
artifacts through the combination of HAWK and SOFI
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