Quantum States of Single-Mode Fields

Qingqiang Kuang

Entangled W state can be applied to quantum information processing in the quantum entanglement,and presented a scheme generation of entangled W state via entangled GHZ state in the single mode cavity field.Three two-level atoms(1,2,3) initially in the W entanglement state,then two atoms 2 and 3 are injected into single mode cavity field to make interaction,while atom 1 is far from the cavity field.The result shows that entangled W state can be generated by manipulating the interactions between cavity field and two atoms in appropriate coupling coefficients when atom 1 is be detected.

Sriram Akella, Kishore Thapliyal, H. S. Mani +1 more

Dynamics of atom–field correlations and single-mode nonclassicalities present in the resonant Jaynes–Cummings model are investigated using negativity and entanglement potential for a set of initial states. The study has revealed the interplay among three different types of nonclassicalities present in the model and established that the nonclassicality is continuously exchanged between the field and atom through atom–field correlations. Further, it is observed that the entanglement potential does not capture all single-mode nonclassicality, and there exists some residual nonclassicality in the reduced single-mode states at the output of the beam splitter that is not captured by the entanglement in which single-mode nonclassicality is quantitatively mapped in Asboth’s criterion. Additional layers of beam splitters are added to deplete all the nonclassicality and to reveal that almost all residual nonclassicality is captured with three layers of beam splitters. Further, the reduced states of the atom and field have zero (non-zero) quantum coherence in the Fock basis when the atom–field correlations are maximum if the field (or atom) has zero (non-zero) quantum coherence initially.

Zeng Ke, Mao-Fa Fang

The entanglement properties of the system of two two-level atoms interacting with a single-mode vacuum field are explored. The quantum entanglement between two two-level atoms and a single-mode vacuum field is investigated by using the quantum reduced entropy; the quantum entanglement between two two-level atoms and that between a single two-level atom and a single-mode vacuum field are studied in terms of the quantum relative entropy. The influences of the atomic dipole–dipole interaction on the quantum entanglement of the system are also discussed. Our results show that three entangled states of two atoms–field, atom–atom and atom–field can be prepared via two two-level atoms interacting with a single-mode vacuum field.

Eduardo C. Marino