Guest lectures and seminars - Page 176
Fred Shultz, Wellesley College, USA will give a talk with title "Decomposing separable states".
This is the first in a joint seminar series organised by the Operator Algebra group (UiO), Several Complex Variable group (UiO) and the CAS group. The plan is to have seminars every other week.
Abstract: This talk will begin with a brief introduction to entanglement and its applications, since that motivates the mathematics to be discussed. In the title of this talk, a state is a positive linear functional on the tensor product of the algebras of m x m and n x n complex matrices. Such a state is separable if it is a convex combination of product states. An interesting open problem is to give a useful criterion for a state to be separable. A related problem is to give a systematic way to find a decomposition of a separable state into a convex combination of product states. This talk will describe such a decomposition for a class of separable states that is of both physical and mathematical interest. This decomposition is also applicable to a class of completely positive maps (which correspond to certain quantum channels). This is joint work with Erik Alfsen.
Paul Kruehner, MAWREM/CMA, holder et seminar med tittelen: Subordination of Hilbert space valued Lévy processes
Magnus Landstad (NTNU) will give a talk with title: Exotic group C*-algebras and noncommutative duality.
Abstract: It has long been known that for a (non-amenable) locally compact group G there are many C*-algebras between the full and reduced group C*-algebra. First I will discuss to what extent these intermediate algebras can be called group C*-algebras. Then I will look at algebras between the full and reduced crossed product, and the various types of coactions (full, maximal, normal) a group can have. To make arguments a little simpler, we shall assume G to be discrete.
Abstract: In groundbreaking work Thomason establishes a fundamental comparison between Bott-inverted algebraic K-theory and étale K-theory with finite coefficients. Over the complex numbers, Walker has shown how to deduce Thomason's theorem using a semi-topological K-homology theory. In joint work with J. Hornbostel we establish an equivariant generalization of Walker's Fundamental Comparison Theorem and use it to deduce the equivariant version of Thomason's theorem for complex varieties with action by a finite group.