## Entanglement in systems of

strongly interacting particles

### Prof. Klaus Capelle

University of Sao Paolo

**Friday, 24 November 2006, 15:30**

Lecture room F, Theoretical Physics, Sölvegatan 14A

**Abstract**:

According to quantum mechanics, entanglement is a fundamental property of
nature. A simple characterization of entanglement is that when a system is
composed of several subsystems, and the wave function of the total system
does not factorize into products of the wave functions of these
subsystems, the system is in an entangled state. Such entangled states can
have surprising properties, which may serve as resources for quantum
information technology and quantum computing. As a fundamental property of
nature, entangled states can occur even in spatially uniform systems of
noninteracting particles.
However, if in the future entanglement is to be exploited for technology
or computation, we must also consider entanglement in systems composed of
strongly interacting particles, such as electrons in a solid, or atoms in
an optical trap. Spatial inhomogeneity (an underlying lattice,
boundaries, impurities, etc.) is another real-life complication, and we
must learn how it affects entanglement. In this talk, I describe recent
research --- making use of model Hamiltonians treated with
density-functional theory --- on the properties of entangled states in
spatially inhomogeneous systems of strongly interacting
particles.