1,528 research outputs found
The Pornography Report: Epistemology, Methodology and Ideology
In a summary section of The Report of the Commission on Obscenity and Pornography, my colleagues and I wrote that . . . persons who are unfamiliar with erotic materials may experience strong and conflicting emotional reactions when first exposed to sexual stimuli. Multiple responses, such as attraction and repulsion to an unfamiliar object, are commonly observed in the research literature on psychosensory stimulation from a variety of nonsexual as well as sexual stimuli. \u27 It may be ironic (but not unpredictable) that the Report we were writing would subsequently generate similarly strong and conflicting emotional responses, for the same reasons: it is so unfamiliar. As I review available evidence concerning the impact of the Report, I detect strength, emotion, repulsion and attraction. And, as in the area of human sexuality, there is considerable misunderstanding
Starting a UAS program
This presentation provides an overview of how to start using unmanned aerial systems from a legal perspective. As UAS become more commonplace and their use expands beyond traditional aviation companies, there is a need for operators to know how to use these vehicles safely and legally. Topics covered include current FAA regulations, operator requirements, vehicle airworthiness, and liability concerns
Hawking Radiation in the Ghost Condensate is Non-Thermal
We consider a Schwarzschild black hole immersed in a ghost condensate
background. It is shown that the Hawking radiation in the quanta of small
perturbations around this background is highly suppressed- in particular it is
not given by a thermal spectrum. This result is in accord with observations
that such black holes can be used to violate the generalized second law of
thermodynamics, and thus cannot have a standard entropy/area relation.Comment: 26 pages; v2: reference added, missing Christoffel symbols included
in appendix, minor typos corrected in equations (39) and (50
Behavior of logarithmic branch cuts in the self-energy of gluons at finite temperature
We give a simple argument for the cancellation of the log(-k^2) terms (k is
the gluon momentum) between the zero-temperature and the temperature-dependent
parts of the thermal self-energy.Comment: 4 page
Gauge Independence of Limiting Cases of One-Loop Electron Dispersion Relation in High-Temperature QED
Assuming high temperature and taking subleading temperature dependence into
account, gauge dependence of one-loop electron dispersion relation is
investigated in massless QED at zero chemical potential. The analysis is
carried out using a general linear covariant gauge. The equation governing the
gauge dependence of the dispersion relation is obtained and used to prove that
the dispersion relation is gauge independent in the limiting case of momenta
much larger than . It is also shown that the effective mass is not
influenced by the leading temperature dependence of the gauge dependent part of
the effective self-energy. As a result the effective mass, which is of order
, does not receive a correction of order from one loop, independent
of the gauge parameter.Comment: Revised and enlarged version, 14 pages, Revte
Thermal quark production in ultra-relativistic nuclear collisions
We calculate thermal production of u, d, s, c and b quarks in
ultra-relativistic heavy ion collisions. The following processes are taken into
account: thermal gluon decay (g to ibar i), gluon fusion (g g to ibar i), and
quark-antiquark annihilation (jbar j to ibar i), where i and j represent quark
species. We use the thermal quark masses, ,
in all the rates. At small mass (), the production is largely
dominated by the thermal gluon decay channel. We obtain numerical and analytic
solutions of one-dimensional hydrodynamic expansion of an initially pure glue
plasma. Our results show that even in a quite optimistic scenario, all quarks
are far from chemical equilibrium throughout the expansion. Thermal production
of light quarks (u, d and s) is nearly independent of species. Heavy quark (c
and b) production is quite independent of the transition temperature and could
serve as a very good probe of the initial temperature. Thermal quark production
measurements could also be used to determine the gluon damping rate, or
equivalently the magnetic mass.Comment: 14 pages (latex) plus 6 figures (uuencoded postscript files);
CERN-TH.7038/9
Quasiparticle picture of quarks near chiral transition at finite temperature
We investigate, using a chiral effective model, the quark spectrum in the
critical region of the chiral transition focusing on the effect of the possible
mesonic excitations in the quark-gluon plasma phase. We find that there appears
a novel three-peak structure in the quark spectra. We elucidate the mechanism
of the appearance of the multi-peak structure with the help of a Yukawa model
with an elementary boson.Comment: 4 pages, 5 eps figures, to appear in the proceedings of International
Conference on Strong & Electroweak Matter 2006, Brookhaven National
Laboratory, USA, May 10-13, 200
The Boltzmann Equation in Scalar Field Theory
We derive the classical transport equation, in scalar field theory with a
V(phi) interaction, from the equation of motion for the quantum field. We
obtain a very simple, but iterative, expression for the effective action which
generates all the n-point Green functions in the high-temperature limit. An
explicit closed form is given in the static case.Comment: 10 pages, using RevTeX (corrected TeX misprints
Light-front Schwinger Model at Finite Temperature
We study the light-front Schwinger model at finite temperature following the
recent proposal in \cite{alves}. We show that the calculations are carried out
efficiently by working with the full propagator for the fermion, which also
avoids subtleties that arise with light-front regularizations. We demonstrate
this with the calculation of the zero temperature anomaly. We show that
temperature dependent corrections to the anomaly vanish, consistent with the
results from the calculations in the conventional quantization. The gauge
self-energy is seen to have the expected non-analytic behavior at finite
temperature, but does not quite coincide with the conventional results.
However, the two structures are exactly the same on-shell. We show that
temperature does not modify the bound state equations and that the fermion
condensate has the same behavior at finite temperature as that obtained in the
conventional quantization.Comment: 10 pages, one figure, version to be published in Phys. Rev.
The graviton self-energy in thermal quantum gravity
We show generally that in thermal gravity, the one-particle irreducible
2-point function depends on the choice of the basic graviton fields. We derive
the relevant properties of a physical graviton self-energy, which is
independent of the parametrization of the graviton field. An explicit
expression for the graviton self-energy at high-temperature is given to
one-loop order.Comment: 13 pages, 2 figure
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