Odd Triplet Pairing in clean Superconductor/Ferromagnet heterostructures

We study triplet pairing correlations in clean Ferromagnet (F)/Superconductor (S) nanojunctions, via fully self consistent solution of the Bogoliubov-de Gennes equations. We consider FSF trilayers, with S being an s-wave superconductor, and an arbitrary angle $\alpha$ between the magnetizations of the two F layers. We find that contrary to some previous expectations, triplet correlations, odd in time, are induced in both the S and F layers in the clean limit. We investigate their behavior as a function of time, position, and $\alpha$. The triplet amplitudes are largest at times on the order of the inverse ``Debye'' frequency, and at that time scale they are long ranged in both S and F. The zero temperature condensation energy is found to be lowest when the magnetizations are antiparallel.Comment: Four pages, including four figure

Slush Hydrogen (SLH2) technology development for application to the National Aerospace Plane (NASP)

The National Aerospace Plane (NASP) program is giving us the opportunity to reach new unique answers in a number of engineering categories. The answers are considered enhancing technology or enabling technology. Airframe materials and densified propellants are examples of enabling technology. The National Aeronautics and Space Administration's Lewis Research Center has the task of providing the technology data which will be used as the basis to decide if slush hydrogen (SLH2) will be the fuel of choice for the NASP. The objectives of this NASA Lewis program are: (1) to provide, where possible, verified numerical models of fluid production, storage, transfer, and feed systems, and (2) to provide verified design criteria for other engineered aspects of SLH2 systems germane to a NASP. This program is a multiyear multimillion dollar effort. The present pursuit of the above listed objectives is multidimensional, covers a range of problem areas, works these to different levels of depth, and takes advantage of the resources available in private industry, academia, and the U.S. Government. The NASA Lewis overall program plan is summarized. The initial implementation of the plan will be unfolded and the present level of efforts in each of the resource areas will be discussed. Results already in hand will be pointed out. A description of additionally planned near-term experimental and analytical work is described

Coherent Control and Entanglement in the Attosecond Electron Recollision Dissociation of D2+

We examine the attosecond electron recollision dissociation of D2+ recently demonstrated experimentally [H. Niikura et al., Nature (London) 421, 826 (2003)] from a coherent control perspective. In this process, a strong laser field incident on D2 ionizes an electron, accelerates the electron in the laser field to eV energies, and then drives the electron to recollide with the parent ion, causing D2+ dissociation. A number of results are demonstrated. First, a full dimensional Strong Field Approximation (SFA) model is constructed and shown to be in agreement with the original experiment. This is then used to rigorously demonstrate that the experiment is an example of coherent pump-dump control. Second, extensions to bichromatic coherent control are proposed by considering dissociative recollision of molecules prepared in a coherent superposition of vibrational states. Third, by comparing the results to similar scenarios involving field-free attosecond scattering of independently prepared D2+ and electron wave packets, recollision dissociation is shown to provide an example of wave-packet coherent control of reactive scattering. Fourth, this analysis makes clear that it is the temporal correlations between the continuum electron and D2+ wave packet, and not entanglement, that are crucial for the sub-femtosecond probing resolution demonstrated in the experiment. This result clarifies some misconceptions regarding the importance of entanglement in the recollision probing of D2+. Finally, signatures of entanglement between the recollision electron and the atomic fragments, detectable via coincidence measurements, are identified

A Simple Quantum Model of Ultracold Polar Molecule Collisions

We present a unified formalism for describing chemical reaction rates of trapped, ultracold molecules. This formalism reduces the scattering to its essential features, namely, a propagation of the reactant molecules through a gauntlet of long-range forces before they ultimately encounter one another, followed by a probability for the reaction to occur once they do. In this way, the electric-field dependence should be readily parametrized in terms of a pair of fitting parameters (along with a $C_6$ coefficient) for each asymptotic value of partial wave quantum numbers $|L,M \rangle$. From this, the electric field dependence of the collision rates follows automatically. We present examples for reactive species such as KRb, and non-reactive species, such as RbCs

Poverty analysis using an international cross-country demand system

This paper proposes a new method for ex ante analysis of the poverty impacts arising from policy reforms. Three innovations underlie this approach. The first is the estimation of a global demand system using a combination of micro-data from household surveys and macro-data from the International Comparisons Project (ICP). Estimation is undertaken in a manner that reconciles these two sources of information, explicitly recognizing that per capita national demands are an aggregation of the disaggregated, individual household demands. The second innovation relates to a methodology for post-estimation calibration of the global demand system, giving rise to country-specific demand systems and an associated expenditure function which, when aggregated across the expenditure distribution, reproduce observed per capita budget shares exactly. This leads to the third innovation, which is the establishment of a unique poverty level of utility and an appropriately modified set of Foster-Greer-Thorbecke poverty measures. With these tools in hand, the authors are able to calculate the change in the head-count of poverty, poverty gap, and squared poverty gap arising from policy reforms, where the poverty measures are derived using a unique poverty level of utility, rather than an income or expenditure-based measure. They use these techniques with a demand system for food, other nondurables and services estimated using a combination of 1996 ICP data set and national expenditure distribution data. Calibration is demonstrated for three countries for which household survey expenditure data are used during estimation-Indonesia, the Philippines and Thailand. To show the usefulness of these calibrated models for policy analysis, the authors assess the effects of an assumed 5 percent food price rise as might be realized in the wake of a multilateral trade agreement. Results illustrate the important role of subsistence expenditures at lowest income levels, but of discretionary expenditure at higher income levels. The welfare analysis underscores the relatively large impact of the price hike on poorer households, while a modified Foster-Greer-Thorbecke poverty measure shows that the 5 percent price rise increases the incidence and intensity of poverty in all three cases, although the specific effects vary considerably by country.Markets and Market Access,Economic Theory&Research,Population Policies,Rural Poverty Reduction,Poverty Lines

Mechanisms of two-color laser-induced field-free molecular orientation

Two mechanisms of two-color (\omega + 2\omega) laser-induced field-free molecular orientation, based on the hyperpolarizability and ionization depletion, are explored and compared. The CO molecule is used as a computational example. While the hyperpolarizability mechanism generates small amounts of orientation at intensities below the ionization threshold, ionization depletion quickly becomes the dominant mechanism as soon as ionizing intensities are reached. Only the ionization mechanism leads to substantial orientation (e.g. on the order of || > 0.1). For intensities typical of laser-induced molecular alignment and orientation experiments, the two mechanism lead to robust, characteristic timings of the field-free orientation wave-packet revivals relative to the the alignment revivals and the revival time. The revival timings can be used to detect the active orientation mechanism experimentally

Work-Related Health in Europe: Are Older Workers More at Risk?

This paper uses the fourth European Working Conditions Survey (2005) to address the impact of age on work-related self-reported health outcomes. More specifically, the paper examines whether older workers differ significantly from younger workers regarding their job-related health risk perception, mental and physical health, sickness absence, probability of reporting injury and fatigue. Accounting for the 'healthy worker effect', or sample selection – in so far as unhealthy workers are likely to exit the labour force – we find that as a group, those aged 55-65 years are more 'vulnerable' than younger workers: they are more likely to perceive work-related health and safety risks, and to report mental, physical and fatigue health problems. As previously shown, older workers are more likely to report work-related absence.endogeneity, fatigue, absence, physical health, mental health, healthy worker selection effect