Frontiers of quantum physics

Abstract:

Various schemes for the determination of a single-mode cavity state from the photon statistics of the field both before and after an interaction with one or two level atoms is presented. The state vector from the measured statistics is calculated and its simplicity is shown. The number states and coherent states fall within the class that may be measured with one atom interaction while squeezed states and Schrodinger cats are within those states that may be measured with two atom interaction. The complexity of the data inversion or measured statistics increases as the number of interacting atom increases.

Abstract:

The form of Bell's inequality does not sufficiently measure quantum correlations because there are states that do not violate the inequality, but can be purified by a combination of local interactions and classical communications to yield a state that does not violate the inequality. It is possible to say that a quantum state is entangled or not, but the amount of entanglement cannot easily be determined for general mixed states. Any measure of entanglement has to satisfy specified conditions on the basis of quantum optics before constructing a whole class of good entanglement measures that are geometrically intuitive.