32,548 research outputs found
Flight investigation of the VFR and IFR landing approach characteristics and terminal area airspace requirements for a light STOL airplane
A flight research program was conducted to determine the terminal area instrument flight capabilities of a light STOL airplane. Simulated (hooded) instrument landing approaches were made using steep single-segment and two-segment glide slopes. A brief investigation was also made of the visual flight terminal area capabilities of the aircraft. The results indicated that the airplane could be flown on a 7 deg glide-slope ILS-type approach in still air with an adequate 3 deg margin for downward correction
EuSrMnO: a three-dimensional XY spin glass
The frequency, temperature, and dc-bias dependence of the ac-susceptibility
of a high quality single crystal of the EuSrMnO layered
manganite is investigated. EuSrMnO behaves like a XY spin
glass with a strong basal anisotropy. Dynamical and static scalings reveal a
three-dimensional phase transition near = 18 K, and yield critical
exponent values between those of Heisenberg- and Ising-like systems, albeit
slightly closer to the Ising case. Interestingly, as in the latter system, the
here observed rejuvenation effects are rather weak. The origin and nature of
the low temperature XY spin glass state is discussed.Comment: REVTeX 4 style; 5 pages, 4 figure
The Pairwise Peculiar Velocity Dispersion of Galaxies: Effects of the Infall
We study the reliability of the reconstruction method which uses a modelling
of the redshift distortions of the two-point correlation function to estimate
the pairwise peculiar velocity dispersion of galaxies. In particular, the
dependence of this quantity on different models for the infall velocity is
examined for the Las Campanas Redshift Survey. We make extensive use of
numerical simulations and of mock catalogs derived from them to discuss the
effect of a self-similar infall model, of zero infall, and of the real infall
taken from the simulation. The implications for two recent discrepant
determinations of the pairwise velocity dispersion for this survey are
discussed.Comment: minor changes in the discussion; accepted for publication in ApJ; 8
pages with 2 figures include
Classical transverse Ising spin glass with short- range interaction beyond the mean field approximation
The classical transverse field Ising spin- glass model with short-range
interactions is investigated beyond the mean- field approximation for a real d-
dimensional lattice. We use an appropriate nontrivial modification of the
Bethe- Peierls method recently formulated for the Ising spin- glass. The zero-
temperature critical value of the transverse field and the linear
susceptibility in the paramagnetic phase are obtained analytically as functions
of dimensionality d. The phase diagram is also calculated numerically for
different values of d. In the limit d -> infinity, known mean- field results
are consistently reproduced.Comment: LaTex, 11 pages, 2 figure
Configuration-Space Location of the Entanglement between Two Subsystems
In this paper we address the question: where in configuration space is the
entanglement between two particles located? We present a thought-experiment,
equally applicable to discrete or continuous-variable systems, in which one or
both parties makes a preliminary measurement of the state with only enough
resolution to determine whether or not the particle resides in a chosen region,
before attempting to make use of the entanglement. We argue that this provides
an operational answer to the question of how much entanglement was originally
located within the chosen region. We illustrate the approach in a spin system,
and also in a pair of coupled harmonic oscillators. Our approach is
particularly simple to implement for pure states, since in this case the
sub-ensemble in which the system is definitely located in the restricted region
after the measurement is also pure, and hence its entanglement can be simply
characterised by the entropy of the reduced density operators. For our spin
example we present results showing how the entanglement varies as a function of
the parameters of the initial state; for the continuous case, we find also how
it depends on the location and size of the chosen regions. Hence we show that
the distribution of entanglement is very different from the distribution of the
classical correlations.Comment: RevTex, 12 pages, 9 figures (28 files). Modifications in response to
journal referee
Current--Voltage Characteristics of Two--Dimensional Vortex Glass Models
We have performed Monte Carlo simulations to determine current--voltage
characteristics of two different vortex glass models in two dimensions. The
results confirm the conclusions of earlier studies that there is a transition
at . In addition we find that, as , the linear resistance vanishes
exponentially, and the current scale, , where non-linearities appear in
the -- characteristics varies roughly as , quite different from the
predictions of conventional flux creep theory, . The results for
the two models agree quite well with each other, and also agree fairly well
with recent experiments on very thin films of YBCO.Comment: 18 pages with 10 figures available upon request from R. A. Hyman at
[email protected]. The only change in the new version is the
deletion of an unimportant comment.IUCM94-01
Universality and the five-dimensional Ising model
We solve the long-standing discrepancy between Monte Carlo results and the
renormalization prediction for the Binder cumulant of the five-dimensional
Ising model. Our conclusions are based on accurate Monte Carlo data for systems
with linear sizes up to L=22. A detailed analysis of the corrections to scaling
allows the extrapolation of these results to L=\infinity. Our determination of
the critical point, K_c=0.1139150 (4), is more than an order of magnitude more
accurate than previous estimates.Comment: 6 pages LaTeX, 1 PostScript figure. Uses cite.sty (included) and
epsf.sty. Also available as PostScript and PDF file at
http://www.tn.tudelft.nl/tn/erikpubs.htm
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