Prof Vlatko Vedral FInstP

Abstract:

The recent developments in quantum information have lead to a renewed interest in multi particle quantum mechanics. A two-qubit system displays many of the paradoxical features of quantum mechanics such as superposition and entanglement. Such states can be partially characterized by their degree of impurity and degree of entanglement. We specifically examine the class of states that have the maximum amount of entanglement (EOF) for a given degree of impurity. We show how these states are more entangled than the Werner like state for a given degree of mixture for several measures of entanglement.

Abstract:

We present a rare example of a decay mechanism playing a constructive role in quantum information processing. We show how the state of an atom trapped in a cavity can be teleported to a second atom trapped in a distant cavity by the joint detection of photon leakage from the cavities. The scheme, which is probabilistic, requires only a single three level atom in a cavity. We also show how this scheme can be modified to a teleportation with insurance.

Abstract:

The natural thermal entanglement in an Ising ring in an external magnetic field was studied. The interactions of two qubits via the Ising interaction in a magnetic field orthogonal to the z direction was analyzed. A theorem for the concurrence mixing due to occupation of the ground and the excited state was formulated. The variation of entanglement with the orientation of magnetic field was numerically considered.