Attosecond pulse shaping using partial phase matching

Peer ReviewedPostprint (published version

A generous welfare state can help reduce unemployment - if there are good job opportunities for the jobless.

Are state unemployment benefits a safety net or a hammock for the lazy? In new research, Thomas Biegert explores the effects of benefits on job seekers in 20 European countries and the US. He finds that in some countries, generous benefits are linked with high unemployment rates, while in others, the opposite is the case. This difference, he writes, may ..

Welfare Benefits and Unemployment in Affluent Democracies: The Moderating Role of the Institutional Insider/Outsider Divide

The effect of generous welfare benefits on unemployment is highly contested. The dominant perspective contends that benefits provide disincentive to work, whereas others portray benefits as job-search subsidies that facilitate better job matches. Despite many studies of welfare benefits and unemployment, the literature has neglected how this relationship might vary across institutional contexts. This article investigates how unemployment benefits and minimum income benefits affect unemployment across levels of the institutional insider/outsider divide. I analyze the moderating role of the disparity in employment protection for holders of permanent and temporary contracts and of the configuration of wage bargaining. The analysis combines data from 20 European countries and the United States using the European Union Labour Force Survey and the Current Population Survey 1992-2009. I use a pseudo-panel approach, including fixed effects for sociodemographic groups within countries and interactions between benefits and institutions. The results indicate that unemployment benefits and minimum income benefits successfully subsidize job search and reduce unemployment in labor markets with a moderate institutional insider/outsider divide. However, when there is greater disparity in employment protection and when bargaining either combines low unionization with high centralization or high unionization with low centralization, generous benefits create a disincentive to work, plausibly because attractive job opportunities are scarce

Above-threshold ionization and photoelectron spectra in atomic systems driven by strong laser fields

Above-threshold ionization (ATI) results from strong field laser-matter interaction and it is one of the fundamental processes that may be used to extract electron structural and dynamical information about the atomic or molecular target. Moreover, it can also be used to characterize the laser field itself. Here, we develop an analytical description of ATI, which extends the theoretical Strong Field Approximation (SFA), for both the direct and re-scattering transition amplitudes in atoms. From a non-local, but separable potential, the bound-free dipole and the re-scattering transition matrix elements are analytically computed. In comparison with the standard approaches to the ATI process, our analytical derivation of the re-scattering matrix elements allows us to study directly how the re-scattering process depends on the atomic target and laser pulse features -we can turn on and off contributions having different physical origins or corresponding to different physical mechanisms. We compare SFA results with the full numerical solutions of the time-dependent Schroedinger equation (TDSE) within the few-cycle pulse regime. Good agreement between our SFA and TDSE model is found for the ATI spectrum. Our model captures also the strong dependence of the photoelectron spectra on the carrier envelope phase of the laser field.Comment: 29 pages, 6 figures, submitted to PR