Browsing NTNU Open by Author "Luef, Franz"

Now showing items 1-20 of 36

    • Affine quantum harmonic analysis 

      Berge, Eirik; Berge, Stine Marie; Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2022)

    • The affine Wigner distribution 

      Berge, Eirik; Berge, Stine Marie; Luef, Franz (Peer reviewed; Journal article, 2022)
      We examine the affine Wigner distribution from a quantization perspective with an emphasis on the underlying group structure. One of our main results expresses the scalogram as (affine) convolution of affine Wigner ...

    • Applying quantum harmonic analysis to Convolutional Neural Networks 

      Henninen, Rasmus (Master thesis, 2023)
      I løpet av de siste fem årene har rammeverket for tid-frekvensanalyse blitt komplementert med begreper som blandet tilstandslokalisering operatorer, Cohen-klassen til en operator og dens akkumulerte versjon. Inspirasjonen ...

    • Convolutions for Berezin quantization and Berezin-Lieb inequalities 

      Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2018)
      Concepts and results from quantum harmonic analysis, such as the convolution between functions and operators or between two operators, are identified as the appropriate setting for Berezin quantization and Berezin-Lieb ...

    • Convolutions for Localization Operators 

      Skrettingland, Eirik (Master thesis, 2017)
      The theory of quantum harmonic analysis on phase space introduced by Werner is presented and formulated precisely using the terminology of time-frequency analysis and abstract harmonic analysis. Convolutions of functions ...

    • Convolutions for localization operators 

      Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2018)
      Quantum harmonic analysis on phase space is shown to be linked with localization operators. The convolution between operators and the convolution between a function and an operator provide a conceptual framework for the ...

    • Deformations and Balian-Low theorems for Gabor frames on the adeles 

      Enstad, Ulrik Bo Rufus; Jakobsen, Mads Sielemann; Luef, Franz; Omland, Tron (Journal article; Peer reviewed, 2022)

    • A Duality Principle for Groups II: Multi-frames Meet Super-Frames 

      Balan, Radu; Dutkay, Dorin; Han, Deguang; David, Larson; Luef, Franz (Peer reviewed; Journal article, 2020)
      The duality principle for group representations developed in Dutkay et al. (J Funct Anal 257:1133–1143, 2009), Han and Larson (Bull Lond Math Soc 40:685–695, 2008) exhibits a fact that the well-known duality principle in ...

    • Gabor duality theory for Morita equivalent C*-algebras 

      Austad, Are; Jakobsen, Mads Sielemann; Luef, Franz (Journal article; Peer reviewed, 2020)
      The duality principle for Gabor frames is one of the pillars of Gabor analysis. We establish a far-reaching generalization to Morita equivalence bimodules with some extra properties. For certain twisted group C∗-algebras, ...

    • Gaussian Gabor frames, Seshadri constants and generalized Buser-Sarnak invariants 

      Luef, Franz; Wang, Xu (Peer reviewed; Journal article, 2023)
      We investigate the frame set of regular multivariate Gaussian Gabor frames using methods from Kähler geometry such as Hörmander’s - estimate with singular weight, Demailly’s Calabi–Yau method for Kähler currents and a ...

    • Geometric and Functional Analytic Aspects of Time-Frequency Analysis 

      Berge, Eirik (Doctoral theses at NTNU;2022:74, Doctoral thesis, 2022)
      Sammendrag på norsk Denne avhandlingen omhandler geometriske og funksjonalanalytiske aspekter ved tid-frekvensanalyse. Mer spesifikt drøfter avhandlingen de tre følgende delvis relaterte temaene: Dekomponeringsrom: I ...

    • Ikke-kommutative Sobolev-rom 

      Gulbrandsrud, Haakon Holm (Master thesis, 2017)
      Først blir det essensielle av forkunnskaper introdusert. Dette inneholder den grunnleggende Hilbert C*-modulteorien, definisjonen og konstruksjonen av Moritaekvivalenser samt noen konsekvenser av dette. På disse bimodulene ...

    • A large scale approach to decomposition spaces 

      Luef, Franz; Berge, Eirik (Peer reviewed; Journal article, 2022)
      Decomposition spaces are a class of function spaces constructed out of “well-behaved” coverings and partitions of unity of a set. The structure of the covering determines the properties of the decomposition space. Besov ...

    • Metaplectic transformations and finite group actions on noncommutative tori 

      Chakraborty, Sayan; Luef, Franz (Journal article; Peer reviewed, 2019)
      In this article we describe extensions of some K-theory classes of Heisenberg modules over higher-dimensional noncommutative tori to projective modules over crossed products of non\-commutative tori by finite cyclic groups, ...

    • Metaplectic Transformations for Gabor Frames and Equivalence Bimodules 

      Gjertsen, Michael (Master thesis, 2023)
      Målet med denne avhandlingen er å presentere og utforske en symplektisk tilnærming til gaboranalyse – gaboranalyse er et emne innen tid-frekvens-analyse som er nært knyttet både til informasjon- og kommunikasjonsteknologier ...

    • Mixed-State Localization Operators: Cohen’s Class and Trace Class Operators 

      Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2019)
      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 operators. The idea of localizing a signal ...

    • Modulation spaces as a smooth structure in noncommutative geometry 

      Austad, Are; Luef, Franz (Peer reviewed; Journal article, 2021)
      We demonstrate how to construct spectral triples for twisted group C^*-algebras of lattices in phase space of a second-countable locally compact abelian group using a class of weights appearing in time–frequency analysis. ...

    • Noncommutative Geometry in Wireless Communication Applications 

      Nås, Sindre (Master thesis, 2018)
      The theory of time-frequency analysis is introduced, and basic results on modulation spaces are proved. We describe Gabor frames and prove results which are relevant to application in wireless communication. We outline a ...

    • Nonlinear phase unwinding 

      Jørgensen, Erik (Master thesis, 2018)
      We start of by studying Hardy spaces and Blaschke products. Then we look at a natural nonlinear analogue of Fourier series called the unwinding series. It is obtained through iterative Blaschke factorization and unwinds ...

    • On Accumulated Cohen's Class Distributions and Mixed-State Localization Operators 

      Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2019)
      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 eigenvalues and eigenvectors. Our main focus is ...