3,021 research outputs found
Correlated random fields in dielectric and spin glasses
Both orientational glasses and dipolar glasses possess an intrinsic random
field, coming from the volume difference between impurity and host ions. We
show this suppresses the glass transition, causing instead a crossover to the
low phase. Moreover the random field is correlated with the inter-impurity
interactions, and has a broad distribution. This leads to a peculiar variant of
the Imry-Ma mechanism, with 'domains' of impurities oriented by a few frozen
pairs. These domains are small: predictions of domain size are given for
specific systems, and their possible experimental verification is outlined. In
magnetic glasses in zero field the glass transition survives, because the
random fields are disallowed by time-reversal symmetry; applying a magnetic
field then generates random fields, and suppresses the spin glass transition.Comment: minor modifications, final versio
A calibration of the stellar mass fundamental plane at z ~ 0.5 using the micro-lensing induced flux ratio anomalies of macro-lensed quasars
We measure the stellar mass surface densities of early type galaxies by
observing the micro-lensing of macro-lensed quasars caused by individual stars,
including stellar remnants, brown dwarfs and red dwarfs too faint to produce
photometric or spectroscopic signatures. Instead of observing multiple
micro-lensing events in a single system, we combine single epoch X-ray
snapshots of ten quadruple systems, and compare the measured relative
magnifications for the images with those computed from macro-models. We use
these to normalize a stellar mass fundamental plane constructed using a
Salpeter IMF with a low mass cutoff of 0.1 solar mass and treat the zeropoint
of the surface mass density as a free parameter. Our method measures the
graininess of the gravitational potential produced by individual stars, in
contrast to methods that decompose a smooth total gravitational potential into
two smooth components, one stellar and one dark. We find the median likelihood
value for the normalization factor F by which the Salpeter stellar masses must
be multiplied is 1.23, with a one sigma confidence range, dominated by small
number statistics, of 0.77 < F < 2.10Comment: Revised in response to referee's suggestions and re-submitted to ApJ;
changes to the adopted effective radii propagate to a new value of the factor
F (by which Salpeter stellar masses must be multiplied) of 1.2
Charged Lepton Electric Dipole Moments from TeV Scale Right-handed Neutrinos
We study the connection between charged lepton electric dipole moments,
, and seesaw neutrino mass generation in a simple two Higgs
doublet extension of the Standard Model plus three right-handed neutrinos (RHN)
, . For RHN with hierarchical masses and at least one with mass
in the 10 TeV range we obtain the upper bounds of
e-cm and e-cm. Our scenario favors the normal
mass hierarchy for the light neutrinos. We also calculated the cross section
for e^-e^- \ra W^- W^- in a high luminosity collider with constraints from
neutrinoless double beta decay of nuclei included. Among the rare muon decay
experiments we find that \mu\ra e\gamma is most sensitive and the upper limit
is .Comment: references added, typos correcte
The Luminosity Function of Galaxies in the Las Campanas Redshift Survey
We present the -band luminosity function for a sample of 18678 galaxies,
with average redshift , from the Las Campanas Redshift Survey. The
luminosity function may be fit by a Schechter function with , , and $\phi^* = 0.019 \pm 0.001 \
h^3^{-3}-23.0 \leq M - 5 \log h \leq -17.5b_J \approx 20b_J \approx 20\alpha = -0.7\alpha = -1W_{\lambda} = 5\alphaM^* =
-20.03 \pm 0.03 + 5 \log h\alpha = -0.9 \pm 0.1M^* = -20.22 \pm 0.02 + 5 \log h\alpha = -0.3
\pm 0.1$.
(abridged abstract)Comment: 41 pages, including 13 postscript figures, uses AASTEX v4.0 style
files. Important clarification of R-band definition, plus correction of
luminosity densities and updated references. Main conclusions unchanged.
Final version to appear in Ap
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