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

Conclusion de l'ouvrage "des tuyaux et des hommes"

National audienceThe recent evolution towards more individual solutions for water and sanitation delivery is to be related to the following stakes: 1. The tradeoff between dependance upon a network and the quality of its delivery 2. The territorial dimension of water services 3. The accountability of water services to different levels of governance.L'évolution récente vers des solutions individuelles d'approvisionnement et de traitement de l'eau doit être mise en relation avec les enjeux suivants : 1. le rapport entre dépendance à un réseau et conditions de délivrance 2. la dimension territoriale des usages de l'eau 3. la redevabilité des services vis à vis des différentes échelles de gouvernance

Adiabatic creation of entangled states by a bichromatic field designed from the topology of the dressed eigenenergies

Preparation of entangled pairs of coupled two-state systems driven by a bichromatic external field is studied. We use a system of two coupled spin-1/2 that can be translated into a three-state ladder model whose intermediate state represents the entangled state. We show that this entangled state can be prepared in a robust way with appropriate fields. Their frequencies and envelopes are derived from the topological properties of the model.Comment: 10 pages, 9 figure

Stimulated Raman Adiabatic Passage via bright state in Lambda medium of unequal oscillator strengths

We consider the population transfer process in a Lambda-type atomic medium of unequal oscillator strengths by stimulated Raman adiabatic passage via bright-state (b-STIRAP) taking into account propagation effects. Using both analytic and numerical methods we show that the population transfer efficiency is sensitive to the ratio q_p/q_s of the transition oscillator strengths. We find that the case q_p>q_s is more detrimental for population transfer process as compared to the case where $q_p \leq q_s$. For this case it is possible to increase medium dimensions while permitting efficient population transfer. A criterion determining the interaction adiabaticity in the course of propagation process is found. We also show that the mixing parameter characterizing the population transfer propagates superluminally

What are the effects of the reliability model uncertainties in the maintenance decisions?

Most of the works proposed for the design of reliability test plans  are  devoted  to  the  guaranty  of  the  reliability performance  of  a  product  but  scarce  of  them  tackles maintenance  issues.  On  the  other  hand,  classical maintenance  optimization  criteria  rarely  take  into  account the variability of the failure parameters due to lack of data, especially when the data collection in the operating phase is expensive.  The  objective  of  this  paper  is  to  highlight through a numerical experiment the impact of the test plan design  defined  here  by  the  number  of  the  products  to  be tested and the test duration on the performance of a classical condition-based maintenance (CBM) policy

Optimal accelerated test plan: optimization procedure using Genetic Algorithm

This paper describes an optimization procedure using Genetic Algorithm to define an optimal accelerated test plan considering an economic approach. We introduce a general framework to obtain plans of optimal accelerate tests with a specific objective, such as cost. The objective is to minimize the costs involved in testing without reducing the quality of the data obtained. The optimal test plans are defined by considering prior knowledge of reliability, including the reliability function and its scale and shape parameters, and the appropriate model to characterize the accelerated life. This information is used in Bayesian inference to optimize the test plan. To perform optimization, a specific genetic algorithm is decribed and applied to obtain the best test plan. This procedure is then illustrated on a numerical example

Development of optimal accelerated test plan

This paper describes an optimal accelerated test plan considering an economic approach. We introduce a general framework to obtain plans of optimal accelerate tests with a specific objective, such as cost. The optimal test plans are defined by considering prior knowledge of reliability, including the reliability function and its scale and shape parameters, and the appropriate model to characterize the accelerated life. This information is used in Bayesian inference to optimize the test plan. The prior knowledge contains the uncertainty on real reliability of new product. So, the proposed methodology consists of defining an optimal accelerated testing plan while considering an objective function based on economic value, using Bayesian inference for optimizing the test plan, and using the uncertainty of the parameters to obtain a robust, optimal testing plan. The objective function consists of two terms: the cost linked to testing activities and the cost associated with operation of the product. Finally, we will develop our optimal plan by extending our approach to include theoretical formulation of the various degrees of freedom with respect to the parameters. To complete this development, we need to improve the algorithm of optimization. To obtain the best test plan, we propose an optimization procedure using the genetic algorithm. The proposed method will be illustrated by a numerical example based on a well-known problem

Hitch-hiking effect and linkage disequilibrium: the example of two closely linked loci in the pig, Halothane Sensitivity (HAL) and Phosphohexose Isomerase (PHI)

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