243 research outputs found
Modified Laplace transformation method at finite temperature: application to infra-red problems of N component theory
Modified Laplace transformation method is applied to N component
theory and the finite temperature problem in the massless limit is re-examined
in the large N limit. We perform perturbation expansion of the dressed thermal
mass in the massive case to several orders and try the massless approximation
with the help of modified Laplace transformation. The contribution with
fractional power of the coupling constant is recovered from the truncated
massive series. The use of inverse Laplace transformation with respect to the
mass square is crucial in evaluating the coefficients of fractional power
terms.Comment: 16pages, Latex, typographical errors are correcte
Effective Field Theory Approach to High-Temperature Thermodynamics
An effective field theory approach is developed for calculating the
thermodynamic properties of a field theory at high temperature and weak
coupling . The effective theory is the 3-dimensional field theory obtained
by dimensional reduction to the bosonic zero-frequency modes. The parameters of
the effective theory can be calculated as perturbation series in the running
coupling constant . The free energy is separated into the contributions
from the momentum scales and , respectively. The first term can be
written as a perturbation series in . If all forces are screened at the
scale , the second term can be calculated as a perturbation series in
beginning at order . The parameters of the effective theory satisfy
renormalization group equations that can be used to sum up leading logarithms
of . We apply this method to a massless scalar field with a
interaction, calculating the free energy to order and the
screening mass to order .Comment: 40 pages, LaTeX, 5 uuecoded figure
Integrable Hierarchies and Information Measures
In this paper we investigate integrable models from the perspective of
information theory, exhibiting various connections. We begin by showing that
compressible hydrodynamics for a one-dimesional isentropic fluid, with an
appropriately motivated information theoretic extension, is described by a
general nonlinear Schrodinger (NLS) equation. Depending on the choice of the
enthalpy function, one obtains the cubic NLS or other modified NLS equations
that have applications in various fields. Next, by considering the integrable
hierarchy associated with the NLS model, we propose higher order information
measures which include the Fisher measure as their first member. The lowest
members of the hiearchy are shown to be included in the expansion of a
regularized Kullback-Leibler measure while, on the other hand, a suitable
combination of the NLS hierarchy leads to a Wootters type measure related to a
NLS equation with a relativistic dispersion relation. Finally, through our
approach, we are led to construct an integrable semi-relativistic NLS equation.Comment: 11 page
X-ray Imaging of Transplanar Liquid Transport Mechanisms in Single Layer Textiles
Understanding the
penetration of liquids within textile fibers
is critical for the development of next-generation smart textiles.
Despite substantial research on liquid penetration in the plane of
the textile, little is known about how the liquid penetrates in the
thickness direction. Here we report a time-resolved high-resolution
X-ray measurement of the motion of the liquid–air interface
within a single layer textile, as the liquid is transported across
the textile thickness following the deposition of a droplet. The measurement
of the time-dependent position of the liquid meniscus is made possible
by the use of ultrahigh viscosity liquids (dynamic viscosity from
10<sup>5</sup> to 2.5 × 10<sup>6</sup> times larger than
water). This approach enables imaging due to the slow penetration
kinetics. Imaging results suggest a three-stage penetration process
with each stage being associated with one of the three types of capillary
channels existing in the textile geometry, providing insights into
the effect of the textile structure on the path of the three-dimensional
liquid meniscus. One dimensional kinetics studies show that our data
for the transplanar penetration depth Δ<i>x</i><sub>L</sub> vs time do not conform to a power law, and that the measured
rate of penetration for long times is smaller than that predicted
by Lucas–Washburn kinetics, challenging commonly held assumptions
regarding the validity of power laws when applied to relatively thin
textiles
Hard Non-commutative Loops Resummation
The non-commutative version of the euclidean theory is
considered. By using Wilsonian flow equations the ultraviolet renormalizability
can be proved to all orders in perturbation theory. On the other hand, the
infrared sector cannot be treated perturbatively and requires a resummation of
the leading divergencies in the two-point function. This is analogous to what
is done in the Hard Thermal Loops resummation of finite temperature field
theory. Next-to-leading order corrections to the self-energy are computed,
resulting in contributions in the massless case, and
in the massive one.Comment: 4 pages, 3 figures. The resummation procedure is now discussed also
at finite ultraviolet cut-off. Minor changes in abstract and references.
Final version to be published in Physical Review Letter
The Free Energy of High Temperature QED to Order From Effective Field Theory
Massless quantum electrodynamics is studied at high temperature and zero
chemical potential. We compute the Debye screening mass to order and
the free energy to order } by an effective field theory approach,
recently developed by Braaten and Nieto. Our results are in agreement with
calculations done in resummed perturbation theory. This method makes it
possible to separate contributions to the free energy from different momentum
scales (order and ) and provides an economical alternative to
computations in the full theory which involves the dressing of internal
propagators.Comment: 10 pages Latex, 6 figure
On the screening of static electromagnetic fields in hot QED plasmas
We study the screening of static magnetic and electric fields in massless
quantum electrodynamics (QED) and massless scalar electrodynamics (SQED) at
temperature . Various exact relations for the static polarisation tensor are
first reviewed and then verified perturbatively to fifth order (in the
coupling) in QED and fourth order in SQED, using different resummation
techniques. The magnetic and electric screening masses squared, as defined
through the pole of the static propagators, are also calculated to fifth order
in QED and fourth order in SQED, and their gauge-independence and
renormalisation-group invariance is checked. Finally, we provide arguments for
the vanishing of the magnetic mass to all orders in perturbation theory.Comment: 37 pages, 8 figure
Aging display's effect on interpretation of digital pathology slides
It is our conjecture that the variability of colors in a pathology image
effects the interpretation of pathology cases, whether it is diagnostic
accuracy, diagnostic confidence, or workflow efficiency. In this paper, digital
pathology images are analyzed to quantify the perceived difference in color
that occurs due to display aging, in particular a change in the maximum
luminance, white point, and color gamut. The digital pathology images studied
include diagnostically important features, such as the conspicuity of nuclei.
Three different display aging models are applied to images: aging of luminance
& chrominance, aging of chrominance only, and a stabilized luminance &
chrominance (i.e., no aging). These display models and images are then used to
compare conspicuity of nuclei using CIE deltaE2000, a perceptual color
difference metric. The effect of display aging using these display models and
images is further analyzed through a human reader study designed to quantify
the effects from a clinical perspective. Results from our reader study indicate
significant impact of aged displays on workflow as well as diagnosis as follow.
As compared to the originals (no-aging), slides with the effect of aging
simulated were significantly more difficult to read (p-value of 0.0005) and
took longer to score (p-value of 0.02). Moreover, luminance+chrominance aging
significantly reduced inter-session percent agreement of diagnostic scores
(p-value of 0.0418)
The Three Loop Equation of State of QED at High Temperature
We present the three loop contribution (order ) to the pressure of
massless quantum electrodynamics at nonzero temperature. The calculation is
performed within the imaginary time formalism. Dimensional regularization is
used to handle the usual, intermediate stage, ultraviolet and infrared
singularities, and also to prevent overcounting of diagrams during resummation.Comment: ANL-HEP-PR-94-02, SPhT/94-054 (revised final version
Can degenerate bound states occur in one dimensional quantum mechanics?
We point out that bound states, degenerate in energy but differing in parity,
may form in one dimensional quantum systems even if the potential is
non-singular in any finite domain. Such potentials are necessarily unbounded
from below at infinity and occur in several different contexts, such as in the
study of localised states in brane-world scenarios. We describe how to
construct large classes of such potentials and give explicit analytic
expressions for the degenerate bound states. Some of these bound states occur
above the potential maximum while some are below. Various unusual features of
the bound states are described and after highlighting those that are ansatz
independent, we suggest that it might be possible to observe such parity-paired
degenerate bound states in specific mesoscopic systems.Comment: 10 pages, 2 figures, to appear in Europhysics Letter
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