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Quantum phase estimation is an important component in diverse quantum algorithms. However, it suffers from spectral leakage, when the reciprocal of the record length is not an integer multiple of the unknown phase, which incurs an accuracy…

Quantum Physics · Physics 2022-05-17 Yifeng Xiong , Soon Xin Ng , Gui-Lu Long , Lajos Hanzo

Calculations of highly excited and delocalized molecular vibrational states are computationally challenging tasks, which strongly depends on the choice of coordinates for describing vibrational motions. We introduce a new method that…

This paper proposes a new approach to construct high quality space-filling sample designs. First, we propose a novel technique to quantify the space-filling property and optimally trade-off uniformity and randomness in sample designs in…

Measuring attenuation coefficients is a fundamental problem that can be solved with diverse techniques such as X-ray or optical tomography and lidar. We propose a novel approach based on the observation of a sample from a few different…

Optimization and Control · Mathematics 2017-01-11 Valentin Debarnot , Jonas Kahn , Pierre Weiss

We study the determination of the second-order normal form for perturbed Hamiltonians $H_{\epsilon}=H_0 +\epsilon H_1 +\frac{\epsilon^2}{2} H_2$, relative to the periodic flow of the unperturbed Hamiltonian $H_0$. The formalism presented…

Mathematical Physics · Physics 2014-05-06 M. Avendaño-Camacho , J. A. Vallejo , Yu. Vorobjev

We propose a new approach to the spectral theory of perturbed linear operators , in the case of a simple isolated eigenvalue. We obtain two kind of results: ''radius bounds'' which ensure perturbation theory applies for perturbations up to…

Spectral Theory · Mathematics 2025-04-08 Benoît Kloeckner

In recent years, spectral graph neural networks, characterized by polynomial filters, have garnered increasing attention and have achieved remarkable performance in tasks such as node classification. These models typically assume that…

Machine Learning · Computer Science 2025-02-25 Kangkang Lu , Yanhua Yu , Hao Fei , Xuan Li , Zixuan Yang , Zirui Guo , Meiyu Liang , Mengran Yin , Tat-Seng Chua

In this paper, we present Gauss's law-preserving spectral methods and their efficient solution algorithms for curl-curl source and eigenvalue problems in two and three dimensions arising from Maxwell's equations. Arbitrary order…

Numerical Analysis · Mathematics 2024-03-01 Sen Lin , Huiyuan Li , Zhiguo Yang

A simple and efficient variational method is introduced to accelerate the convergence of the eigenenergy computations for a Hamiltonian H with singular potentials. Closed-form analytic expressions in N dimensions are obtained for the matrix…

Mathematical Physics · Physics 2009-11-10 Nasser Saad , Richard L. Hall , Qutaibeh D. Katatbeh

The flux reconstruction (FR) approach offers a flexible framework for describing a range of high-order numerical schemes; including nodal discontinuous Galerkin and spectral difference schemes. This is accomplished through the use of…

Numerical Analysis · Mathematics 2020-06-25 Will Trojak , Freddie Witherden

In this paper, a new filtering method is presented for simultaneous noise reduction and enhancement of signals using a fractal scalar conservation law which is simply the forward heat equation modified by a fractional anti-diffusive term of…

Analysis of PDEs · Mathematics 2011-09-07 Pascal Azerad , Afaf Bouharguane , Jean-François Crouzet

We study the moduli space of the spectral curves $y^2=W'(z)^2+f(z)$ which characterize the vacua of $\mathcal{N}=1$ U(n) supersymmetric gauge theories with an adjoint Higgs field and a polynomial tree level potential $W(z)$. It is shown…

Mathematical Physics · Physics 2015-06-12 Boris Konopelchenko , Luis Martínez Alonso , Elena Medina

The limits of frequency resolution in nano-NMR experiments have been discussed extensively in recent years. It is believed that there is a crucial difference between the ability to resolve a few frequencies and the precision of estimating a…

Wavelet frames for $L^2({\mathbb R})$ can be characterized by means of spectral techniques. This work uses spectral formulas to determine all the tight wavelet frames for $L^2({\mathbb R})$ with a fixed finite number of generators of…

Functional Analysis · Mathematics 2019-01-24 F. Gómez-Cubillo , S. Villullas

The Wigner Transform (WT) has been extensively used in the formulation of phase-space models for a variety of wave propagation problems including high-frequency limits, nonlinear and random waves. It is well known that the WT features…

Analysis of PDEs · Mathematics 2015-05-19 Agissilaos G. Athanassoulis

We put forward a new type of spectral method for the direct numerical simulation of flows where anisotropy or very fine boundary layers are present. The mean idea is to take advantage of the fact that such structures are dissipative and…

Fluid Dynamics · Physics 2014-03-18 Kacper Kornet , Alban Pothérat

A remarkable mathematical property -- somehow hidden and recently rediscovered -- allows obtaining the eigenvectors of a Hermitian matrix directly from their eigenvalues. That opens the possibility to get the wavefunctions from the…

Computational Physics · Physics 2020-06-12 Dario Mitnik , Santiago Mitnik

The calculation of the partial widths of the Z boson in the effective scheme is discussed. Simple formulae for Sin^2 theta_eff^lept, M_W, and Gamma_l in the on-shell, MS, and effective renormalization schemes are presented. Their domain of…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. Ferroglia , G. Ossola , M. Passera , A. Sirlin

In two-phase image segmentation, convex relaxation has allowed global minimisers to be computed for a variety of data fitting terms. Many efficient approaches exist to compute a solution quickly. However, we consider whether the nature of…

Numerical Analysis · Mathematics 2018-08-01 Jack Spencer

Various forms of regularization in learning tasks strive for different notions of simplicity. This paper presents a spectral regularization technique, which attaches a unique inductive bias to sequence modeling based on an intuitive concept…

Machine Learning · Computer Science 2022-11-07 Kaiwen Hou , Guillaume Rabusseau