Blar i NTNU Open på forfatter "Luef, Franz"

Convolutions for Berezin quantization and BerezinLieb 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 BerezinLieb ... 
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 ... 
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 timefrequency analysis and abstract harmonic analysis. Convolutions of functions ... 
A Duality Principle for Groups II: Multiframes Meet SuperFrames
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 wellknown 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 farreaching generalization to Morita equivalence bimodules with some extra properties. For certain twisted group C∗algebras, ... 
Ikkekommutative Sobolevrom
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 ... 
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 Ktheory classes of Heisenberg modules over higherdimensional noncommutative tori to projective modules over crossed products of non\commutative tori by finite cyclic groups, ... 
MixedState Localization Operators: Cohen’s Class and Trace Class Operators
Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2019)We study mixedstate localization operators from the perspective of Werner’s operator convolutions which allows us to extend known results from the rankone case to trace class operators. The idea of localizing a signal ... 
Noncommutative Geometry in Wireless Communication Applications
Nås, Sindre (Master thesis, 2018)The theory of timefrequency 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 MixedState Localization Operators
Luef, Franz; Skrettingland, Eirik (Journal article; Peer reviewed, 2019)Recently we introduced mixedstate 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 ... 
Polyanalytic Toeplitz Operators: Isomorphisms, Symbolic Calculus and Approximation of Weyl Operators
Keller, Johannes; Luef, Franz (Peer reviewed; Journal article, 2021)We discuss an extension of Toeplitz quantization based on polyanalytic functions. We derive isomorphism theorem for polyanalytic Toeplitz operators between weighted SobolevFock spaces of polyanalytic functions, which are ... 
Rational Noncommutative Tori and Gabor Frames
Enstad, Ulrik Bo Rufus (Master thesis, 2016)A link between noncommutative geometry and timefrequency analysis is used to show that the TKNN equation violates existence results for Gabor frames with atoms in the Schwartz space. In particular, we use that the Schwartz ... 
Sampling and periodization of generators of Heisenberg modules
Jakobsen, Mads Sielemann; Luef, Franz (Journal article; Peer reviewed, 2019)This paper considers generators of Heisenberg modules in the case of twisted group C∗algebras of closed subgroups of locally compact abelian (LCA) groups and how the restriction and/or periodization of these generators ... 
Solitons of general topological charge over noncommutative tori
Dabrowski, Ludwik; Jakobsen, Mads Sielemann; Landi, Giovanni; Luef, Franz (Peer reviewed; Journal article, 2021)We study solitons of general topological charge over noncommutative tori from the perspective of timefrequency analysis. These solitons are associated with vector bundles of higher rank, expressed in terms of vectorvalued ... 
The Algebraic Bivariant ConnesChern Character
Austad, Are (Master thesis, 2017)In this thesis we present many properties of bivariant periodic cyclic homology with the purpose of then constructing two bivariant ConnesChern characters from algebraic versions of Kasparov's KKtheory with values in ... 
The Balian–Low theorem and noncommutative tori
Luef, Franz (Journal article; Peer reviewed, 2018)We point out a link between the theorem of Balian and Low on the nonexistence of welllocalized Gabor–Riesz bases and a constant curvature connection on projective modules over noncommutative tori. 
TimeFrequency Analysis Meets Quantum Harmonic Analysis
Skrettingland, Eirik (Doctoral theses at NTNU;2021:152, Doctoral thesis, 2021)The subject of this thesis is the study of quantum harmonic analysis and timefrequency analysis, and in particular the intersection of these two fields. Quantum harmonic analysis is studied abstractly both by obtaining new ... 
Timefrequency analysis on the adeles over the rationals
Enstad, Ulrik Bo Rufus; Jakobsen, Mads Sielemann; Luef, Franz (Journal article; Peer reviewed, 2019)We show that the construction of Gabor frames in with generators in and with respect to timefrequency shifts from a rectangular lattice is equivalent to the construction of certain Gabor frames for over the adeles over ... 
Twisted Convolution Algebras and Applications to Gabor Analysis
Austad, Are (Doctoral theses at NTNU;2021:155, Doctoral thesis, 2021)This thesis concerns several aspects of twisted convolution algebras, with a particular focus on problems arising in Gabor analysis. A significant portion of the thesis is dedicated to the study of Hilbert C modules known ...