Quantum state engineering in a cavity by Stark chirped rapid adiabatic passage

We propose a robust scheme to generate single-photon Fock states and atom-photon and atom-atom entanglement in atom-cavity systems. We also present a scheme for quantum networking between two cavity nodes using an atomic channel. The mechanism is based on Stark-chirped rapid adiabatic passage (SCRAP) and half-SCRAP processes in a microwave cavity. The engineering of these states depends on the design of the adiabatic dynamics through the static and dynamic Stark shifts.Comment: 7 pages, 8 figures, to be appeared in PL

On the topology of adiabatic passage

We examine the topology of eigenenergy surfaces characterizing the population transfer processes based on adiabatic passage. We show that this topology is the essential feature for the analysis of the population transfers and the prediction of its final result. We reinterpret diverse known processes, such as stimulated Raman adiabatic passage (STIRAP), frequency-chirped adiabatic passage and Stark-chirped rapid adiabatic passage (SCRAP). Moreover, using this picture, we display new related possibilities of transfer. In particular, we show that we can selectively control the level which will be populated in STIRAP process in Lambda or V systems by the choice of the peak amplitudes or the pulse sequence

Adiabatic tracking for photo- and magneto-association of Bose-Einstein condensates with Kerr nonlinearities

We develop the method of adiabatic tracking for photo- and magneto-association of Bose-Einstein atomic condensates with models that include Kerr type nonlinearities. We show that the inclusion of these terms can produce qualitatively important modifications in the adiabatic dynamics, like the appearance of bifurcations, in which the trajectory that is being tracked loses its stability. As a consequence the adiabatic theorem does not apply and the adiabatic transfer can be strongly degraded. This degradation can be compensated by using fields that are strong enough compared with the values of the Kerr terms. The main result is that, despite these potentially detrimental features, there is always a choice of the detuning that leads to an efficient adiabatic tracking, even for relatively weak fields

Atom-photon, atom-atom and photon-photon entanglement preparation via fractional adiabatic passage

We propose a relatively robust scheme to generate maximally entangled states of (i) an atom and a cavity photon, (ii) two atoms in their ground states, and (iii) two photons in two spatially separate high-Q cavities. It is based on the interaction via fractional adiabatic passage of a three-level atom traveling through a cavity mode and a laser beam. The presence of optical phases is emphasized.Comment: 6 pages, 7 figures. We have changed the title, the abstract and the text. The references have been updated. (Accepted by Phys. Rev. A

Pricing Strategies for User-Provided Connectivity Services

User-provided connectivity (UPC) services offer a possible alternative, orcomplement, to existing infrastructure-based connectivity. A userallows other users to occasionally connect through its home base inexchange for reciprocation, or possibly compensation. This service modelexhibits strong positive and negative externalities. A large user basemakes the service more attractive, as it offers more connectivity options toroaming users, but it also implies a greater volume of (roaming) trafficpassing through a user\u27s home base, which can increase congestion. Theseinteractions make it difficult to predict the eventual success of such aservice offering, and in particular how to effectively price it. This paperinvestigates a two-price policy where the first price is an introductory price that expires onceservice adoption reaches a certain level. The paper uses a simplifiedanalytical model to investigate pricing strategies under this policy, and their sensitivity to changesin system parameters. The insight and practicalguidelines this yields are validated numerically under morerealistic conditions

Experimental Aspects of Highly Accelerated Life Tests

Experimental aspects of High Accelerated Life Tests (HALT) are presented. A statistical analysis of test results which allows to define the different characteristic areas of a product (operating and destruction limits) is given. In particular, some tests on electronic board using thermal and vibration stresses have been investigated

Added value of bleach sedimentation microscopy for diagnosis of tuberculosis: a cost-effectiveness study.

SETTING: Bleach sedimentation is a method used to increase the diagnostic yield of sputum microscopy for countries with a high prevalence of human immunodeficiency virus (HIV) infection and limited resources. OBJECTIVES: To compare the relative cost-effectiveness of different microscopy approaches in diagnosing tuberculosis (TB) in Kenya. METHODS: An analytical decision tree model including cost and effectiveness measures of 10 combinations of direct (D) and overnight bleach (B) sedimentation microscopy was constructed. Data were drawn from the evaluation of the bleach sedimentation method on two specimens (first on the spot [1] and second morning [2]) from 644 TB suspects in a peripheral health clinic. Incremental cost per smear-positive detected case was measured. Costs included human resources and materials using a micro-costing evaluation. RESULTS: All bleach-based microscopy approaches detected significantly more cases (between 23.3% for B1 and 25.9% for B1+B2) than the conventional D1+D2 approach (21.0%). Cost per tested case ranged between respectively euro 2.7 and euro 4.5 for B1 and B1+D2+B2. B1 and B1+B2 were the most cost-effective approaches. D1+B2 and D1+B1 were good alternatives to avoid using approaches exclusively based on bleach sedimentation microscopy. CONCLUSIONS: Among several effective microscopy approaches used, including sodium hypochlorite sedimentation, only some resulted in a limited increase in the laboratory workload and would be most suitable for programmatic implementation