English
Related papers

Related papers: The Error in Rayleigh's Approximative Period

200 papers

Laplace approximations are commonly used to approximate high-dimensional integrals in statistical applications, but the quality of such approximations as the dimension of the integral grows is not well understood. In this paper, we prove a…

Statistics Theory · Mathematics 2018-08-21 Helen Ogden

We develop a systematic derivation for the Limber approximation to the angular cross-power spectrum of two random fields, as a series expansion in 1/(\ell+1/2). This extended Limber approximation can be used to test the accuracy of the…

Astrophysics · Physics 2008-12-18 Marilena LoVerde , Niayesh Afshordi

The coarsening and wavenumber selection of striped states growing from random initial conditions are studied in a non-relaxational, spatially extended, and far-from-equilibrium system by performing large-scale numerical simulations of…

Pattern Formation and Solitons · Physics 2009-11-10 M. R. Paul , K-H. Chiam , M. C. Cross , P. F. Fischer

We consider time-harmonic Maxwell's equations set in an heterogeneous medium with perfectly conducting boundary conditions. Given a divergence-free right-hand side lying in $L^2$, we provide a frequency-explicit approximability estimate…

Numerical Analysis · Mathematics 2022-08-03 T. Chaumont-Frelet , P. Vega

We consider the long-standing problem of Rayleigh-Taylor instability with variable acceleration, and focus on the early-time dynamics of an interface separating incompressible ideal fluids of different densities subject to an acceleration…

Plasma Physics · Physics 2019-06-25 Des L. Hill , Aklant K. Bhowmick , Snezhana I. Abarzhi

The general, multidimensional barrier crossing problem for diffusive processes under the action of conservative forces is studied with the goal of developing tractable approximations. Particular attention is given to the effect of different…

Statistical Mechanics · Physics 2025-09-03 James F. Lutsko

In this paper we consider a sub-diffusion problem where the fractional time derivative is approximated either by the L1 scheme or by Convolution Quadrature. We propose new interpretations of the numerical schemes which lead to a posteriori…

Numerical Analysis · Mathematics 2022-03-02 Lehel Banjai , Charalambos G. Makridakis

We investigate the first moment of the difference between $\psi(x;q,a)$ and Vaughan's approximation, in a certain range of $q$. We show that this last approximation is significantly more precise than the classical $x/\phi(q)$, and that it…

Number Theory · Mathematics 2015-08-31 Daniel Fiorilli

High-frequency wave propagation is often modelled by nonlinear Friedrichs systems where both the differential equation and the initial data contain the inverse of a small parameter $\varepsilon$, which causes oscillations with wavelengths…

Analysis of PDEs · Mathematics 2024-02-21 Julian Baumstark , Tobias Jahnke

Numerical simulations of turbulent Rayleigh-B\'enard convection in an ideal gas, using either the anelastic approximation or the fully compressible equations, are compared. Theoretically, the anelastic approximation is expected to hold in…

Solar and Stellar Astrophysics · Physics 2015-05-27 Jan Verhoeven , Thomas Wiesehöfer , Stephan Stellmach

This is the first part in a series of two papers that concern with the quantitative analysis of the electromagnetic field enhancement and anomalous diffraction by a periodic array of subwavelength slits. The scattering problem in the…

Analysis of PDEs · Mathematics 2017-06-08 Junshan Lin , Hai Zhang

Given the first 20-100 coefficients of a typical generating function of the type that arises in many problems of statistical mechanics or enumerative combinatorics, we show that the method of differential approximants performs surprisingly…

Statistical Mechanics · Physics 2016-10-12 Anthony J Guttmann

The problem of approximate string matching is important in many different areas such as computational biology, text processing and pattern recognition. A great effort has been made to design efficient algorithms addressing several variants…

Data Structures and Algorithms · Computer Science 2008-07-29 Dimitris Papamichail , Georgios Papamichail

Approximate string matching is the problem of finding all factors of a text t of length n that are at a distance at most k from a pattern x of length m. Approximate circular string matching is the problem of finding all factors of t that…

Data Structures and Algorithms · Computer Science 2016-04-26 Carl Barton , Costas S. Iliopoulos , Solon P. Pissis

The problem on the Cramer-Rao Lower Bounds (CRLBs) for the joint time delay and Doppler stretch estimation of an extended target is considered in this paper. The integral representations of the CRLBs for both the time delay and the Doppler…

Signal Processing · Electrical Eng. & Systems 2018-08-30 Tong Zhao , Tianyao Huang

In this paper we deal with the care one must have in adopting approximations in regard with terms he chooses to leave behind in the particular case of the expression valid for the maximum period of a long pendulum oscillating near Earth's…

Classical Physics · Physics 2016-05-16 Rogério Netto Suave , José Alexandre Nogueira

We determine the Lagrange function in Taylor polynomial approximation by solving an appropriate initial-value problem. Hence, we determine the remainder term which we then approximate by means of a natural cubic spline. This results in a…

Numerical Analysis · Mathematics 2023-03-06 J. S. C. Prentice

The Rayleigh-Ritz (RR) method finds the stationary values, called Ritz values, of the Rayleigh quotient on a given trial subspace as approximations to eigenvalues of a Hermitian operator $A$. If the trial subspace is $A$-invariant, the Ritz…

Numerical Analysis · Mathematics 2010-01-08 Andrew V. Knyazev , Merico E. Argentati

In this paper, we establish a priori estimates for the positive solutions to a higher-order fractional Laplace equation on a bounded domain by a blowing-up and rescaling argument. To overcome the technical difficulty due to the high-order…

Analysis of PDEs · Mathematics 2023-08-07 Yugao Ouyang , Meiqing Xu , Ran Zhuo

We study the cubic weakly nonlinear Schr\"odinger equation with randomized spatially quasi-periodic initial data in higher dimensions. Under a polynomial decay assumption in Fourier space, we establish a {\em Large Deviations Principle} for…

Probability · Mathematics 2026-04-21 Fei Xu , Yong Li