Wednesday, June 9th, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Maria Jivulescu (Politehnica University, Timisoara) Title: Entanglement criteria in quantum information theory Abstract: In my talk I will recall basic facts about separable/entanglement quantum states and the main classical criteria for distinguish them. Then I will focus on a new introducedContinue reading “Operator Theory Seminar: Entanglement criteria in quantum information theory”

# Category Archives: Operator Theory Seminar

## Operator Theory Seminar: Index theory for tensor products of pseudodifferential operators

Wednesday, June 2nd, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Karsten Bohlen (Regensburg) Title: Index theory for tensor products of pseudodifferential operators Abstract: In this talk we consider systems of tensor products of pseudodifferential operators. Motivating examples are double Cauchy integral operators that occur in the study of certain boundary valueContinue reading “Operator Theory Seminar: Index theory for tensor products of pseudodifferential operators”

## Operator Theory Seminar: Dilations of unitary tuples

Wednesday, May 26, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Orr Shalit (Technion, Haifa) Title: Dilations of unitary tuples Abstract: We study the space of all d-tuples of unitaries using dilation theory. If U and V are two d-tuples of unitaries, we ask what is the minimal constant C such thatContinue reading “Operator Theory Seminar: Dilations of unitary tuples”

## Operator Theory Seminar: Entrywise positivity preservers: connections to analysis, covariance estimation, and combinatorics

Wednesday, May 19, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Apoorva Khare (Indian Institute of Science, and Analysis & Probability Research Group, Bangalore) Title: Entrywise positivity preservers: connections to analysis, covariance estimation, and combinatorics Abstract: Which functions preserve positive semidefiniteness (psd) when applied entrywise to psd matrices? This question has aContinue reading “Operator Theory Seminar: Entrywise positivity preservers: connections to analysis, covariance estimation, and combinatorics”

## Operator Theory Seminar: A constructive approach to Schäffer’s conjecture

Wednesday, May 12, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Rachid Zarouf (Institut de Mathématiques de Marseille) Title: A constructive approach to Schäffer’s conjecture Abstract: We prove results that we found on our way to a deeper understanding of Schäffer’s conjecture about inverse operators. In 1970 J.J. Schäffer proved that forContinue reading “Operator Theory Seminar: A constructive approach to Schäffer’s conjecture”

## Operator Theory Seminar: Free spectrahedra and compatibility of quantum measurements

Wednesday, April 28, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Ion Nechita (University of Toulouse) Title: Free spectrahedra and compatibility of quantum measurements Abstract: I will start by reviewing (free) spectrahedra, central objects in free convex analysis. I will then introduce the notion of measurement incompatibility in quantum information theory, andContinue reading “Operator Theory Seminar: Free spectrahedra and compatibility of quantum measurements”

## Operator Theory Seminar: Spectrum and analytic functional calculus for Clifford operators via stem functions

Wednesday, April 21, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Florian-Horia Vasilescu (University of Lille) Title: Spectrum and analytic functional calculus for Clifford operators via stem functions Abstract: The main purpose of this work is the construction of an analytic functional calculus for Clifford operators, which act on certain modules overContinue reading “Operator Theory Seminar: Spectrum and analytic functional calculus for Clifford operators via stem functions”

## Operator Theory Seminar: Toeplitz operators on the polydisc

Wednesday, March 31, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Jaydeb Sarkar (Bangalore) Title: Toeplitz operators on the polydisc Abstract: Toeplitz operators are one of the most useful and prevalent objects in matrix theory, operator theory, operator algebras, and its related fields. A lot of work has been done in theContinue reading “Operator Theory Seminar: Toeplitz operators on the polydisc”

## Operator Theory Seminar: Topological obstructions to matrix stability of discrete groups

Wednesday, March 24, 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Marius Dadarlat (Purdue University) Title: Topological obstructions to matrix stability of discrete groups Abstract: A discrete countable group is matricially stable if its finite dimensional approximate unitary representations are perturbable to genuine representations in the point-norm topology. We aim to explainContinue reading “Operator Theory Seminar: Topological obstructions to matrix stability of discrete groups”

## Operator Theory Seminar: Separable boundaries for non-hyperbolic groups

Wednesday, March 17 2021, 15:00 A presentation given at the Operator theory seminar. Speaker: Jacopo Bassi (Rome) Title: Separable boundaries for non-hyperbolic groups Abstract: Ozawa proved in 2007 that the nuclear C*-algebra associated to the action of a free group on its boundary sits inside the injective envelope of the reduced C*-algebra of the groupContinue reading “Operator Theory Seminar: Separable boundaries for non-hyperbolic groups”