Zero-point oscillations in the vicinity of atoms

Cataloged from PDF version of article.It is shown that the vacuum fluctuations of an electromagnetic field are concentrated near atoms. This effect worsens the quantum limit of precision of the measurements in atomic systems. (C) 2001 American Institute of Physics

Easy Monitored Entangled States

We discuss the generation and monitoring of durable atomic entangled state via Raman-type process, which can be used in the quantum information processing.Comment: 9 pages, 2 figures, the previous title "Durable Entanglement in Atomic Systems" is replaced by new title, accepted to Appl. Phys. Let

Quantification of entanglement via uncertainties

We show that entanglement of pure multi-party states can be quantified by means of quantum uncertainties of certain basic observables through the use of measure that has been initially proposed in [10] for bipartite systems.Comment: Changed content, references added 7 pages, no figures, PRA in pres

Steady state entanglement of two atoms created by classical driving field

The stabilization of steady state entanglement caused by action of a classical driving field in the system of two-level atoms with the dipole interaction accompanied by spontaneous emission is discussed. An exact solution shows that the maximum amount of concurrence that can be achieved in Lamb-Dicke limit is 0.43, which corresponds to the entanglement $\mathcal{E}_{max}=0.285$ ebit. Dependence of entanglement on interatomic distance and classical driving field is examined numerically.Comment: 14 pages, 2 figure

Quantum phase via the angular momentum

Cataloged from PDF version of article.An approach to the quantum phase, taking into account the process of light generation and extending in this way the operational approach, is proposed. The cosine and sine operators of the phase difference of the two circularly polarized modes are determined with the aid of a polar decomposition of the angular momentum of radiative transition and conservation of the total angular momentum. Application of the approach to the Jaynes-Cummings model for an electric dipole transition shows consistency with the classical definition of the phase difference and with the results of standard operational approach as well