10,855 research outputs found
The Blackbody Radiation Spectrum Follows from Zero-Point Radiation and the Structure of Relativistic Spacetime in Classical Physics
The analysis of this article is entirely within classical physics. Any
attempt to describe nature within classical physics requires the presence of
Lorentz-invariant classical electromagnetic zero-point radiation so as to
account for the Casimir forces between parallel conducting plates at low
temperatures. Furthermore, conformal symmetry carries solutions of Maxwell's
equations into solutions. In an inertial frame, conformal symmetry leaves
zero-point radiation invariant and does not connect it to non-zero-temperature;
time-dilating conformal transformations carry the Lorentz-invariant zero-point
radiation spectrum into zero-point radiation and carry the thermal radiation
spectrum at non-zero temperature into thermal radiation at a different
non-zero-temperature. However, in a non-inertial frame, a time-dilating
conformal transformation carries classical zero-point radiation into thermal
radiation at a finite non-zero-temperature. By taking the no-acceleration
limit, one can obtain the Planck radiation spectrum for blackbody radiation in
an inertial frame from the thermal radiation spectrum in an accelerating frame.
Here this connection between zero-point radiation and thermal radiation is
illustrated for a scalar radiation field in a Rindler frame undergoing
relativistic uniform proper acceleration through flat spacetime in two
spacetime dimensions. The analysis indicates that the Planck radiation spectrum
for thermal radiation follows from zero-point radiation and the structure of
relativistic spacetime in classical physics.Comment: 21 page
Level-1 jet trigger hardware for the ALICE electromagnetic calorimeter at LHC
The ALICE experiment at the LHC is equipped with an electromagnetic
calorimeter (EMCal) designed to enhance its capabilities for jet measurement.
In addition, the EMCal enables triggering on high energy jets. Based on the
previous development made for the Photon Spectrometer (PHOS) level-0 trigger, a
specific electronic upgrade was designed in order to allow fast triggering on
high energy jets (level-1). This development was made possible by using the
latest generation of FPGAs which can deal with the instantaneous incoming data
rate of 26 Gbit/s and process it in less than 4 {\mu}s.Comment: proceeding of TWEPP-10 at Aachen. 6 pages, 4 figure
Techniques for measuring atmospheric aerosols at the High Resolution Fly's Eye experiment
We describe several techniques developed by the High Resolution Fly's Eye
experiment for measuring aerosol vertical optical depth, aerosol horizontal
attenuation length, and aerosol phase function. The techniques are based on
measurements of side-scattered light generated by a steerable ultraviolet laser
and collected by an optical detector designed to measure fluorescence light
from cosmic-ray air showers. We also present a technique to cross-check the
aerosol optical depth measurement using air showers observed in stereo. These
methods can be used by future air fluorescence experiments.Comment: Accepted for publication in Astroparticle Physics Journal 16 pages, 9
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The Distance of the Gamma-ray Binary 1FGL J1018.6-5856
The recently discovered gamma-ray binary 1FGL J1018.6-5856 has a proposed
optical/near-infrared (OIR) counterpart 2MASS 10185560-5856459. We present
Stromgren photometry of this star to investigate its photometric variability
and measure the reddening and distance to the system. We find that the
gamma-ray binary has E(B-V) = 1.34 +/- 0.04 and d = 5.4^+4.6_-2.1 kpc. While
E(B-V) is consistent with X-ray observations of the neutral hydrogen column
density, the distance is somewhat closer than some previous authors have
suggested.Comment: Accepted to PAS
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