353,762 research outputs found
Tailorable infrared sensing device with strain layer superlattice structure
An infrared photodetector is formed of a heavily doped p-type Ge sub x Si sub 1-x/Si superlattice in which x is pre-established during manufacture in the range 0 to 100 percent. A custom-tailored photodetector that can differentiate among close wavelengths in the range of 2.7 to 50 microns is fabricated by appropriate selection of the alloy constituency value, x, to establish a specific wavelength at which photodetection cutoff will occur
Diffusion semigroup on manifolds with time-dependent metrics
Let , on a differential manifold equipped
with time-depending complete Riemannian metric , where
is the Laplacian induced by and is a
family of -vector fields. We first present some explicit criteria for
the non-explosion of the diffusion processes generated by ; then establish
the derivative formula for the associated semigroup; and finally, present a
number of equivalent semigroup inequalities for the curvature lower bound
condition, which include the gradient inequalities, transportation-cost
inequalities, Harnack inequalities and functional inequalities for the
diffusion semigroup
On Bayesian Oracle Properties
When model uncertainty is handled by Bayesian model averaging (BMA) or
Bayesian model selection (BMS), the posterior distribution possesses a
desirable "oracle property" for parametric inference, if for large enough data
it is nearly as good as the oracle posterior, obtained by assuming
unrealistically that the true model is known and only the true model is used.
We study the oracle properties in a very general context of quasi-posterior,
which can accommodate non-regular models with cubic root asymptotics and
partial identification. Our approach for proving the oracle properties is based
on a unified treatment that bounds the posterior probability of model
mis-selection. This theoretical framework can be of interest to Bayesian
statisticians who would like to theoretically justify their new model selection
or model averaging methods in addition to empirical results. Furthermore, for
non-regular models, we obtain nontrivial conclusions on the choice of prior
penalty on model complexity, the temperature parameter of the quasi-posterior,
and the advantage of BMA over BMS.Comment: 31 page
Validity of two Higgs doublet models with a scalar color octet up to a high energy scale
We have recently studied theoretical constraints on the parameters of a 2HDM
augmented with a color-octet scalar. In this paper we consider the consequences
of requiring the model to remain valid up to very high energy scales, such as
the GUT scale. The acceptable region of parameter space is reduced when one
insists on vacuum stability, perturbative unitarity and the absence of Landau
poles below a given scale. As the scale to which we require the model to be
valid is increased, the acceptable region of parameter space for the 2HDM
sector is reduced in such a way that it approaches the alignment limit,
, and the masses of , and are pushed
closer to each other. The parameters of the color octet sector are also
restricted to an increasingly smaller region.Comment: 16 pages, 5 figures; referenced added; typos fixe
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