11,946 research outputs found
Complete Positivity for Mixed Unitary Categories
In this article we generalize the \CP^\infty-construction of dagger
monoidal categories to mixed unitary categories. Mixed unitary categories
provide a setting, which generalizes (compact) dagger monoidal categories and
in which one may study quantum processes of arbitrary (infinite) dimensions.
We show that the existing results for the \CP^\infty-construction hold in
this more general setting. In particular, we generalize the notion of
environment structures to mixed unitary categories and show that the
\CP^\infty-construction on mixed unitary categories is characterized by this
generalized environment structure.Comment: Lots of figure
The Mass-Loss Return From Evolved Stars to The Large Magellanic Cloud VI: Luminosities and Mass-Loss Rates on Population Scales
We present results from the first application of the Grid of Red Supergiant
and Asymptotic Giant Branch ModelS (GRAMS) model grid to the entire evolved
stellar population of the Large Magellanic Cloud (LMC). GRAMS is a pre-computed
grid of 80,843 radiative transfer (RT) models of evolved stars and
circumstellar dust shells composed of either silicate or carbonaceous dust. We
fit GRAMS models to ~30,000 Asymptotic Giant Branch (AGB) and Red Supergiant
(RSG) stars in the LMC, using 12 bands of photometry from the optical to the
mid-infrared. Our published dataset consists of thousands of evolved stars with
individually determined evolutionary parameters such as luminosity and
mass-loss rate. The GRAMS grid has a greater than 80% accuracy rate
discriminating between Oxygen- and Carbon-rich chemistry. The global dust
injection rate to the interstellar medium (ISM) of the LMC from RSGs and AGB
stars is on the order of 1.5x10^(-5) solar masses/yr, equivalent to a total
mass injection rate (including the gas) into the ISM of ~5x10^(-3) solar
masses/yr. Carbon stars inject two and a half times as much dust into the ISM
as do O-rich AGB stars, but the same amount of mass. We determine a bolometric
correction factor for C-rich AGB stars in the K band as a function of J - K
color, BC(K) = -0.40(J-K)^2 + 1.83(J-K) + 1.29. We determine several IR color
proxies for the dust mass-loss rate (MLR) from C-rich AGB stars, such as log
(MLR) = (-18.90)/((K-[8.0])+3.37)-5.93. We find that a larger fraction of AGB
stars exhibiting the `long-secondary period' phenomenon are O-rich than stars
dominated by radial pulsations, and AGB stars without detectable mass-loss do
not appear on either the first-overtone or fundamental-mode pulsation
sequences.Comment: 19 pages, 19 figure
Advanced turboprop vibratory characteristics
The assembly of SR5 advanced turboprop blades to develop a structural dynamic data base for swept props is reported. Steady state blade deformation under centrifugal loading and vibratory characteristics of the rotor assembly were measured. Vibration was induced through a system of piezoelectric crystals attached to the blades. Data reduction procedures are used to provide deformation, mode shape, and frequencies of the assembly at predetermined speeds
The Human Development Index Adjusted for Efficient Resource Utilization
human development index, data envelopment analysis, efficiency, congestion and scale economics
On Schwinger Pair Creation in Gravity and in Closed Superstring Theory
We investigate the Schwinger pair creation process in the context of
gravitational models with the back reaction of the electric field included in
the geometry. The background is also an exact solution of type II superstring
theory, where the electric field arises by Kaluza-Klein reduction. We obtain a
closed formula for the pair creation rate that incorporates the gravitational
back reaction. At weak fields it has the same structure as the general
Schwinger formula, albeit pairs are produced by a combination of Schwinger and
Unruh effect, the latter due to the presence of a Rindler horizon. In four
spacetime dimensions, the rate becomes constant at strong electric fields. For
states with mass of Kaluza-Klein origin, the rate has a power-like dependence
in the electric field, rather than the familiar (non-perturbative) exponential
dependence. We also reproduce the same formula from the string partition
function for winding string states. Finally, we comment on the generalization
to excited string states.Comment: 21 page
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