Cluster state machine gun / A harsh noise entanglement detector

6 05/2015

Wednesday, 06 May. 2015, 15:00 - 16:00

Presenter: Thomas Nutz & Pete Shadbolt; Imperial Collage London, GB
Host: M. Aspelmeyer
Where: Schrödingerroom, 4th Floor, Boltzmanngasse 5, 1090 Wien

Cluster state machine gun

I will introduce a scheme for the generation of long strings of photonic linear Cluster state. Experimental realization of this scheme seems possible in charged Quantum Dot or NV centre single photon sources. Basic experimental requirements and challenges will be discussed.


A harsh noise entanglement detector

I will show how the distribution of absolute expectation values over all local observables reveals information about entanglement and purity for 2-qubit states. By measuring states in random local bases, concurrence and purity can be bounded. This extends to larger systems: W states can be discriminated from GHZ states, for example. This method allows unknown states to be reliably characterized despite unknown, uncontrolled local drift - e.g. polarization drift in an optical fiber.