12,834 research outputs found
Inequalities for electron-field correlation functions
I show that there exists a class of inequalities between correlation
functions of different orders of a chaotic electron field. These inequalities
lead to the antibunching effect and are a consequence of the fact that
electrons are fermions -- indistinguishable particles with antisymmetric
states. The derivation of the inequalities is based on the known form of the
correlation functions for the chaotic state and on the properties of matrices
and determinants.Comment: 8 pages Latex2e, 2 eps figure
Correlation Functions and Spin
The k-electron correlation function of a free chaotic electron beam is
derived with the spin degree of freedom taken into account. It is shown that it
can be expressed with the help of correlation functions for a polarized
electron beam of all orders up to k and the degree of spin polarization. The
form of the correlation function suggests that if the electron beam is not
highly polarized, observing multi-particle correlations should be difficult.
The result can be applied also to chaotic photon beams, the degree of spin
polarization being replaced by the degree of polarization.Comment: 6 pages, 1 eps figure, accepted to Phys. Rev.
The Effects of Negative Legacies on the Adjustment of Parentally Bereaved Children and Adolescents
This is a report of a qualitative analysis of a sample of bereaved families in which one parent died and in which children scored in the clinical range on the Child Behavior Check List. The purpose of this analysis was to learn more about the lives of these children. They were considered to be at risk of developing emotional and behavioral problems associated with the death. We discovered that many of these “high risk” children had a continuing bond with the deceased that was primarily negative and troubling for them in contrast to a comparison group of children not at risk from the same study. Five types of legacies, not mutually exclusive, were identified: health related, role related, personal qualities, legacy of blame, and an emotional legacy. Coping behavior on the part of the surviving parent seemed to make a difference in whether or not a legacy was experienced as negative
X-ray Emission from the Radio Jet in 3C 120
We report the discovery of X-ray emission from a radio knot at a projected
distance of 25" from the nucleus of the Seyfert galaxy, 3C 120. The data were
obtained with the ROSAT High Resolution Imager (HRI). Optical upper limits for
the knot preclude a simple power law extension of the radio spectrum and we
calculate some of the physical parameters for thermal bremsstrahlung and
synchrotron self-Compton models. We conclude that no simple model is consistent
with the data but if the knot contains small regions with flat spectra, these
could produce the observed X-rays (via synchrotron emission) without being
detected at other wavebands.Comment: 6 pages latex plus 3 ps/eps figures. Uses 10pt.sty and
emulateapj.sty. Accepted for publication in the ApJ (6 Jan 99
Programmable telemetry system Patent
Time division multiplexed telemetry transmitting system controlled by programmed memor
Low-latitude auroras: the magnetic storm of 14–15 May 1921
We review solar/geophysical data relating to the great magnetic storm of 14–15 May 1921, with emphasis on observations of the low-latitude visual aurora. From the reports we have gathered for this event, the lowest geomagnetic latitude of de6nite overhead aurora (coronal form) was 40° and the lowest geomagnetic latitude from which auroras were observed on the poleward horizon in the northern hemisphere was 30°. For comparison, corresponding overhead/low-latitude values of 48°/32° and 41°/20° were reported for the great auroras on 28–29 August and 1–2 September 1859, respectively. However, for the 1921 event, there is a report of aurora from Apia, Samoa, in the southern hemisphere, within 13◦ of the geomagnetic equator. This report by professional observers appears to be credible, based on the aurora description and timing, but is puzzling because of the discrepancy with the lowest latitude of observation in the northern hemisphere and the great implied auroral height (~ 2000 km, assuming overhead aurora at Auckland, New Zealand). We discuss various possibilities that might account for this observation
Low-latitude auroras: the magnetic storm of 14–15 May 1921
We review solar/geophysical data relating to the great magnetic storm of 14–15 May 1921, with emphasis on observations of the low-latitude visual aurora. From the reports we have gathered for this event, the lowest geomagnetic latitude of de6nite overhead aurora (coronal form) was 40° and the lowest geomagnetic latitude from which auroras were observed on the poleward horizon in the northern hemisphere was 30°. For comparison, corresponding overhead/low-latitude values of 48°/32° and 41°/20° were reported for the great auroras on 28–29 August and 1–2 September 1859, respectively. However, for the 1921 event, there is a report of aurora from Apia, Samoa, in the southern hemisphere, within 13◦ of the geomagnetic equator. This report by professional observers appears to be credible, based on the aurora description and timing, but is puzzling because of the discrepancy with the lowest latitude of observation in the northern hemisphere and the great implied auroral height (~ 2000 km, assuming overhead aurora at Auckland, New Zealand). We discuss various possibilities that might account for this observation
PTF11kx: A Type Ia Supernova with Hydrogen Emission Persisting After 3.5 Years
The optical transient PTF11kx exhibited both the characteristic spectral
features of Type Ia supernovae (SNe Ia) and the signature of ejecta interacting
with circumstellar material (CSM) containing hydrogen, indicating the presence
of a nondegenerate companion. We present an optical spectrum at days
after peak from Keck Observatory, in which the broad component of H
emission persists with a similar profile as in early-time observations. We also
present IRAC detections obtained and days after peak,
and an upper limit from ultraviolet imaging at days. We interpret
our late-time observations in context with published results - and reinterpret
the early-time observations - in order to constrain the CSM's physical
parameters and compare to theoretical predictions for recurrent nova systems.
We find that the CSM's radial extent may be several times the distance between
the star and the CSM's inner edge, and that the CSM column density may be two
orders of magnitude lower than previous estimates. We show that the H
luminosity decline is similar to other SNe with CSM interaction, and
demonstrate how our infrared photometry is evidence for newly formed,
collisionally heated dust. We create a model for PTF11kx's late-time CSM
interaction and find that X-ray reprocessing by photoionization and
recombination cannot reproduce the observed H luminosity, suggesting
that the X-rays are thermalized and that H radiates from collisional
excitation. Finally, we discuss the implications of our results regarding the
progenitor scenario and the geometric properties of the CSM for the PTF11kx
system.Comment: 15 pages, 8 figures, 3 tables; submitted to Ap
Anomalous Chromomagnetic Moments of Quarks and Large Transverse Energy Jets
We consider the jet cross sections for gluons coupling to quarks with an
anomalous chromomagnetic moment. We then apply this to the deviation and bounds
from QCD found in the CDF and D0 Fermilab data, respectively, to find a range
of possible values for the anomalous moments. The quadratic and quartic terms
in the anomalous moments can fit to the rise of a deviation with transverse
energy. Since previous analyses have been done on the top quark total cross
section, here we assume the same moment on all quarks except the top and find
the range TeV for the
CDF data. Assuming the anomalous moment is present only on a charm or bottom
quark which is pair produced results in a range TeV. The magnitudes here are compared with anomalous magnetic moments
that could account for and found to be in the same general range, as well
as not inconsistent with LEP and SLD bounds on .Comment: REVTeX, 11 pages, 2 postscript figure
Some genus 3 curves with many points
Using an explicit family of plane quartic curves, we prove the existence of a
genus 3 curve over any finite field of characteristic 3 whose number of
rational points stays within a fixed distance from the Hasse-Weil-Serre upper
bound. We also provide an intrinsic characterization of so-called Legendre
elliptic curves
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