56 research outputs found
On the accuracy of solving confluent Prony systems
In this paper we consider several nonlinear systems of algebraic equations
which can be called "Prony-type". These systems arise in various reconstruction
problems in several branches of theoretical and applied mathematics, such as
frequency estimation and nonlinear Fourier inversion. Consequently, the
question of stability of solution with respect to errors in the right-hand side
becomes critical for the success of any particular application. We investigate
the question of "maximal possible accuracy" of solving Prony-type systems,
putting stress on the "local" behavior which approximates situations with low
absolute measurement error. The accuracy estimates are formulated in very
simple geometric terms, shedding some light on the structure of the problem.
Numerical tests suggest that "global" solution techniques such as Prony's
algorithm and ESPRIT method are suboptimal when compared to this theoretical
"best local" behavior
Fractal Weyl law for chaotic microcavities: Fresnel's laws imply multifractal scattering
We demonstrate that the harmonic inversion technique is a powerful tool to
analyze the spectral properties of optical microcavities. As an interesting
example we study the statistical properties of complex frequencies of the fully
chaotic microstadium. We show that the conjectured fractal Weyl law for open
chaotic systems [W. T. Lu, S. Sridhar, and M. Zworski, Phys. Rev. Lett. 91,
154101 (2003)] is valid for dielectric microcavities only if the concept of the
chaotic repeller is extended to a multifractal by incorporating Fresnel's laws.Comment: 8 pages, 12 figure
Eigenvectors in the Superintegrable Model II: Ground State Sector
In 1993, Baxter gave eigenvalues of the transfer matrix of the
-state superintegrable chiral Potts model with spin-translation quantum
number , where . In our previous paper we
studied the Q=0 ground state sector, when the size of the transfer matrix
is chosen to be a multiple of . It was shown that the corresponding
matrix has a degenerate eigenspace generated by the generators of
simple algebras. These results enable us to express the transfer matrix
in the subspace in terms of these generators and for
. Moreover, the corresponding eigenvectors of the transfer
matrix are expressed in terms of rotated eigenvectors of .Comment: LaTeX 2E document, using iopart.cls with iopams packages. 17 pages,
uses eufb10 and eurm10 fonts. Typeset twice! vs2: Many changes and additions,
adding 7 pages. vs3: minor corrections. vs4 minor improvement
Development of the Bélanger Equation and Backwater Equation by Jean-Baptiste Bélanger (1828)
A hydraulic jump is the sudden transition from a high-velocity to a low-velocity open channel flow. The application of the momentum principle to the hydraulic jump is commonly called the Bélanger equation, but few know that Bélanger's (1828) treatise was focused on the study of gradually varied open channel flows. Further, although Bélanger understood the rapidly-varied nature of the jump flow, he applied incorrectly the Bernoulli principle in 1828, and corrected his approach 10 years later. In 1828, his true originality lay in the successful development of the backwater equation for steady, one-dimensional gradually-varied flows in an open channel, together with the introduction of the step method, distance calculated from depth, and the concept of critical flow conditions
pyReSpect: A Computer Program to Extract Discrete and Continuous Spectra from Stress Relaxation Experiments
An experimental study on the use of dynamic tests for surveillance of concrete structures
Computational Algorithm for Least Squares Estimation of Parameters in Compartmental Analysis
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