Frontiers of quantum physics

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Classical correlations and entanglement in quantum measurements.

Phys Rev Lett 90:5 (2003) 050401

Abstract:

We analyze a quantum measurement where the apparatus is initially in a mixed state. We show that the amount of information gained in a measurement is not equal to the amount of entanglement between the system and the apparatus, but is instead equal to the degree of classical correlations between the two. As a consequence, we derive an uncertainty-like expression relating the information gain in the measurement and the initial mixedness of the apparatus. Final entanglement between the environment and the apparatus is also shown to be relevant for the efficiency of the measurement.

Entanglement in The Second Quantization Formalism

(2003)

Geometric phase in open systems

(2003)

Authors:

A Carollo, I Fuentes-Guridi, M Franca Santos, V Vedral

Berry's phase in cavity QED: Proposal for observing an effect of field quantization

Physical Review A - Atomic, Molecular, and Optical Physics 67:6 (2003) 638041-638044

Authors:

A Carollo, M Fran莽a Santos, V Vedral

Classicality of spin-coherent states via entanglement and distinguishability

Physical Review A Atomic Molecular and Optical Physics 67:4 (2003) 421131-4211310

Authors:

D Markham, V Vedral

Abstract:

A study was performed on the classicality of spin-coherent states via entanglement and distinguishability. The distinguishability of the spin-coherent states was established using the representation of Majorana. The resistance to entanglement generation of the spin-coherent states, when passed through a beam splitter was traced.