The Faber–Krahn inequality for the short-time Fourier transform

F Nicola, P Tilli - Inventiones mathematicae, 2022 - Springer
In this paper we solve an open problem concerning the characterization of those
measurable sets Ω⊂ R 2 d that, among all sets having a prescribed Lebesgue measure, can …

On accumulated spectrograms

LD Abreu, K Gröchenig, JL Romero - Transactions of the American …, 2016 - ams.org
We study the eigenvalues and eigenfunctions of the time-frequency localization operator $
H_\Omega $ on a domain $\Omega $ of the time-frequency plane. The eigenfunctions are …

Stability of the Faber-Krahn inequality for the short-time Fourier transform

J Gómez, A Guerra, JPG Ramos, P Tilli - Inventiones mathematicae, 2024 - Springer
We prove a sharp quantitative version of the Faber–Krahn inequality for the short-time
Fourier transform (STFT). To do so, we consider a deficit δ (f; Ω) which measures by how …

Donoho-Logan large sieve principles for modulation and polyanalytic Fock spaces

LD Abreu, M Speckbacher - Bulletin des Sciences Mathématiques, 2021 - Elsevier
We obtain estimates for the L p-norm of the short-time Fourier transform (STFT) for functions
in modulation spaces, providing information about the concentration on a given subset of R …

[HTML][HTML] Affine quantum harmonic analysis

E Berge, SM Berge, F Luef, E Skrettingland - Journal of Functional Analysis, 2022 - Elsevier
We develop a quantum harmonic analysis framework for the affine group. This encapsulates
several examples in the literature such as affine localization operators, covariant integral …

A Faber–Krahn inequality for Wavelet transforms

JPG Ramos, P Tilli - Bulletin of the London Mathematical …, 2023 - Wiley Online Library
For some special window functions ψ α∈ H 2 (C+) ψ_α∈H^2(C^+), we prove that, over all
sets Δ⊂ C+ Δ⊂C^+ of fixed hyperbolic measure ν (Δ) ν(Δ), those for which the Wavelet …

Mixed-state localization operators: Cohen's class and trace class operators

F Luef, E Skrettingland - Journal of Fourier Analysis and Applications, 2019 - Springer
We study mixed-state localization operators from the perspective of Werner's operator
convolutions which allows us to extend known results from the rank-one case to trace class …

On accumulated Cohen's class distributions and mixed-state localization operators

F Luef, E Skrettingland - Constructive Approximation, 2020 - Springer
Recently we introduced mixed-state localization operators associated with a density
operator and a (compact) domain in phase space. We continue the investigations of their …

[HTML][HTML] Optimal Gabor frame bounds for separable lattices and estimates for Jacobi theta functions

M Faulhuber, S Steinerberger - Journal of Mathematical Analysis and …, 2017 - Elsevier
We study sharp frame bounds of Gabor frames for integer redundancy with the standard
Gaussian window and prove that the square lattice optimizes both the lower and the upper …

The norm of time-frequency and wavelet localization operators

F Nicola, P Tilli - Transactions of the American Mathematical Society, 2023 - ams.org
Time-frequency localization operators (with Gaussian window) $ L_F: L^ 2 (\mathbb {R}^
d)\to L^ 2 (\mathbb {R}^ d) $, where $ F $ is a weight in $\mathbb {R}^{2d} $, were …