Measures and dynamics of entanglement

Quantum information technology largely relies on a precious and fragile resource, quantum entanglement, a highly nontrivial manifestation of the coherent superposition of states of composite quantum systems. However, our knowledge on the time evolution of this resource under realistic conditions, when corrupted by environment-induced decoherence, is hitherto rather limited, and general statements on entanglement dynamics in open systems are scarce. The lecture will start from a short recollection of the basic elements of entanglement theory for finite dimensional composite mixed quantum states, spell out the central difficulties for the formulation of a general theory, and then address various aspects of open system entanglement dynamics in variable dimensions. Also the issue of direct experimental probing of the entanglement inscribed into an unknown mixed quantum state will be briefly discussed.