Frontiers of quantum physics

Abstract:

Remote information concentration, the reverse process of quantum telecloning, is presented. In this scheme, quantum information originally from a single qubit, but now distributed into three spatially separated qubits, is remotely concentrated back to a single qubit via an initially shared entangled state without performing any global operations. This entangled state is a single unlockable bound entangled state and we analyze its properties.

Abstract:

The generation of entanglement through global phase functions was studied. Necessary and sufficient conditions for the application of global phases to the pure product state to result in entanglement were obtained. The maximum entanglement creation by global phases was considered as well as its corresponding examples.

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.