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Can one characterise the Fourier decay of a product measure in terms of the Fourier decay of its marginals? We make inroads on this question by describing the Fourier spectrum of a product measure in terms of the Fourier spectrum of its…

Classical Analysis and ODEs · Mathematics 2024-05-30 Jonathan M. Fraser

We introduce and study the \emph{Fourier spectrum} which is a continuously parametrised family of dimensions living between the Fourier dimension and the Hausdorff dimension for both sets and measures. We establish some fundamental theory…

Classical Analysis and ODEs · Mathematics 2026-05-28 Jonathan M. Fraser

Based on diffraction theory and the propagation of the light, Fourier optics is a powerful tool allowing the estimation of a visible-range imaging system to transfer the spatial frequency components of an object. The analyses of the imaging…

General Physics · Physics 2018-06-05 Stephane Perrin , Paul Montgomery

We prove non-trivial upper and lower bounds for the "Spectrum of Singularities" of Fourier Series with polynomial frequencies. The Spectrum of Singularities of a function f gives the Hausdorff dimension of the set of points with a given…

Number Theory · Mathematics 2012-09-03 Fernando Chamizo , Adrián Ubis

It is shown here that precision is gained by analyzing the interferometric spectra directly from the interferograms, with no previous Fourier transformation to put them in the standard frequency domain. The method is based on the…

Instrumentation and Detectors · Physics 2018-04-20 Miguel Lagos , Rodrigo Paredes , Cesar Retamal

We link the problem of estimating the lower Hausdorff dimension of PDE or Fourier constrained measures with Harnack's inequalities for the heat equation. Our approach provides new estimates in the case of Fourier constraints.

Classical Analysis and ODEs · Mathematics 2020-10-29 Dmitriy Stolyarov

The changes in brightness of an astronomical source as a function of time are key probes into that source's physics. Periodic and quasi-periodic signals are indicators of fundamental time (and length) scales in the system, while stochastic…

Instrumentation and Methods for Astrophysics · Physics 2023-08-08 Matteo Bachetti , Daniela Huppenkothen

This algorithm is designed to perform numerical transforms to convert data from the temporal domain into the spectral domain. This algorithm obtains the spectral magnitude and phase by studying the Coefficient of Determination of a series…

Optics · Physics 2026-05-20 Matthew David Marko

In this paper we show an alternative way of defining Fourier Series and Transform by using the concept of convolution with exponential signals. This approach has the advantage of simplifying proofs of transforms properties and, in our view,…

History and Overview · Mathematics 2022-01-20 Francisco Mota

Universal regularities of the Fourier spectrum of signal, generated by complex analytic map at the period-tripling bifurcations accumulation point are considered. The difference between intensities of the subharmonics at the values of…

Chaotic Dynamics · Physics 2007-05-23 O. B. Isaeva

We construct examples of uncountable compact subsets of complex numbers with the property that any Borel measure on the circle group taking values of its Fourier coefficients from this set has natural spectrum. For measures with Fourier…

Functional Analysis · Mathematics 2017-05-17 Przemysław Ohrysko , Michał Wojciechowski

For a real sequence of length of m = nl, we may deduce its congruence derivative sequence with length of l. The discrete Fourier transform of original sequence can be calculated by the discrete Fourier transform of the congruence derivative…

Signal Processing · Electrical Eng. & Systems 2019-04-19 Jiasong Wang , Changchuan Yin

This work proposes the development and study of a novel technique for the generation of fractal descriptors used in texture analysis. The novel descriptors are obtained from a multiscale transform applied to the Fourier technique of fractal…

Data Analysis, Statistics and Probability · Physics 2012-01-24 João Batista Florindo , Odemir Martinez Bruno

There is a class of physical filtration processes where the input is adequately modeled by a continuous periodic function f (x) of bounded variation over its period, and the output depends only on certain harmonics of the Fourier expansion…

General Mathematics · Mathematics 2024-12-17 Vladimir Sluchak

VQC can be understood through the lens of Fourier analysis. It is already well-known that the function space represented by any circuit architecture can be described through a truncated Fourier sum. We show that the spectrum available to…

Machine Learning · Computer Science 2024-11-08 Marco Wiedmann , Maniraman Periyasamy , Daniel D. Scherer

We present a characterization of the sets that appear as Fourier spectra of measures in terms of the existence of a strongly continuous representation of the ambient group that has a wandering vector for the given set.

Functional Analysis · Mathematics 2012-09-05 Dorin Ervin Dutkay , Palle E. T. Jorgensen

If $X$ is a closed subset of the real line, denote by $\GG_X$ the supremum of the size of the gap in the Fourier spectrum, taken over all non-trivial finite complex measures supported on $X$. In this paper we attempt to find $\GG_X$ in…

Complex Variables · Mathematics 2009-08-21 A. Poltoratski

We describe a method to probe the spectral fluctuations of a transition over broad ranges of frequencies and timescales with the high spectral resolution of Fourier spectroscopy, and a temporal resolution as high as the excited state…

This paper establishes connections between the group-Fourier transform and the geometry of measures in the Heisenberg group. Firstly, it is shown that if the Fourier transform of a compactly supported, finite, Radon measure is square…

Functional Analysis · Mathematics 2020-02-27 Fernando Roman-Garcia

This paper relates uniform alpha-Hoelder continuity, or alpha-dimensionality, of spectral measures in an arbitrary interval to the Fourier transform of the measure. This is used to show that scaling exponents of exponential sums obtained…

chao-dyn · Physics 2009-10-28 A. Hof
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