32,032 research outputs found
A rescaled method for RBF approximation
In the recent paper [8], a new method to compute stable kernel-based
interpolants has been presented. This \textit{rescaled interpolation} method
combines the standard kernel interpolation with a properly defined rescaling
operation, which smooths the oscillations of the interpolant. Although
promising, this procedure lacks a systematic theoretical investigation. Through
our analysis, this novel method can be understood as standard kernel
interpolation by means of a properly rescaled kernel. This point of view allow
us to consider its error and stability properties
A rescaled method for RBF approximation
A new method to compute stable kernel-based interpolants
has been presented by the second and third authors. This rescaled interpolation method combines the
standard kernel interpolation with a properly defined rescaling operation, which
smooths the oscillations of the interpolant. Although promising, this procedure
lacks a systematic theoretical investigation.
Through our analysis, this novel method can be understood as standard
kernel interpolation by means of a properly rescaled kernel. This point of view
allow us to consider its error and stability properties.
First, we prove that the method is an instance of the Shepard\u2019s method,
when certain weight functions are used. In particular, the method can reproduce
constant functions.
Second, it is possible to define a modified set of cardinal functions strictly
related to the ones of the not-rescaled kernel. Through these functions, we
define a Lebesgue function for the rescaled interpolation process, and study its
maximum - the Lebesgue constant - in different settings.
Also, a preliminary theoretical result on the estimation of the interpolation
error is presented.
As an application, we couple our method with a partition of unity algorithm.
This setting seems to be the most promising, and we illustrate its behavior with
some experiments
A Modular Sewing Kit for Entanglement Wedges
We relate the Riemann curvature of a holographic spacetime to an entanglement
property of the dual CFT state: the Berry curvature of its modular
Hamiltonians. The modular Berry connection encodes the relative bases of nearby
CFT subregions while its bulk dual, restricted to the code subspace, relates
the edge-mode frames of the corresponding entanglement wedges. At leading order
in 1/N and for sufficiently smooth HRRT surfaces, the modular Berry connection
simply sews together the orthonormal coordinate systems covering neighborhoods
of HRRT surfaces. This geometric perspective on entanglement is a promising new
tool for connecting the dynamics of entanglement and gravitation.Comment: 26 pages + Appendices, 4 figure
Killing gauge for the 0-brane on coset superspace
How to gauge fix \k-symmetry for the super 0-brane action on in Killing gauge properly is discussed in order to find the superconformal
mechanics which describes super 0-brane probes moving on .
The dependence on the coordinate frame for the proper Killing gauge is
considered and the subtleties of gauge-fixing \k-symmetry in Killing gauge
are analysed explicitly. It is found that the Killing gauge works indeed
without the imcompatibility if the magnetic charge of the super 0-brane is
nonzero.Comment: 14 pages, LaTeX2
Euclidean Path Integral, D0-Branes and Schwarzschild Black Holes in Matrix Theory
The partition function in Matrix theory is constructed by Euclidean path
integral method. The D0-branes, which move around in the finite region with a
typical size of Schwarzschild radius, are chosen as the background. The mass
and entropy of the system obtained from the partition function contain the
parameters of the background. After averaging the mass and entropy over the
parameters, we find that they match the properties of 11D Schwarzschild black
holes. The period \b of Euclidean time can be identified with the reciprocal
of the boosted Hawking temperature. The entropy is shown to be proportional
to the number of Matrix theory partons, which is a consequence of the
D0-brane background.Comment: 15 pages, Late
Fine-structure diagnostics of neutral carbon toward HE 0515-4414
New high-resolution high signal-to-noise spectra of the damped Lyman
(DLA) system toward the quasi-stellar object HE 0515-4414 reveal
absorption lines of the multiplets 2 and 3 in \ion{C}{i}. The resonance lines
are seen in two components with total column densities of
and , respectively. The comparision of theoretical
calculations of the relative fine-structure population with the ratios of the
observed column densities suggests that the \ion{C}{i} absorbing medium is
either very dense or exposed to very intense UV radiation. The upper limit on
the local UV energy density is 100 times the galactic UV energy density, while
the upper limit on the \ion{H}{i} number density is 110 cm. The
excitation temperatures of the ground state fine-structure levels of
and K, respectively, are consistent with the temperature-redshift
relation predicted by the standard Friedmann cosmology. The cosmic microwave
background radiation (CMBR) is only a minor source of the observed
fine-structure excitation.Comment: 5 pages, 5 figures, uses A&A macro package, gzipped tar archive,
accepted by A&
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