Periodic orbit theory for Rydberg atoms in external fields

Although hydrogen in external fields is a paradigm for the application of periodic orbits and the Gutzwiller trace formula to a real system, the trace formula has never been applied successfully to other Rydberg atoms. We show that spectral fluctuations of general Rydberg atoms are given with remarkable precision by the addition of diffractive terms. Previously unknown features in atomic spectra are exposed: there are new modulations that are neither periodic orbits nor combinations of periodic orbits; “core shadowing” generally decreases primitive periodic orbit amplitudes but can also lead to increases

Porto Oscillation Code (POSC)

The Porto Oscillation Code (POSC) has been developed in 1995 and improved over the years, with the main goal of calculating linear adiabatic oscillations for models of solar-type stars. It has also been used to estimate the frequencies and eigenfunctions of stars from the pre-main sequence up to the sub-giant phase, having a mass between 0.8 and 4 solar masses. The code solves the linearised perturbation equations of adiabatic pulsations for an equilibrium model using a second order numerical integration method. The possibility of using Richardson extrapolation is implemented. Several options for the surface boundary condition can be used. In this work we briefly review the key ingredients of the calculations, namely the equations, the numerical scheme and the output.Comment: Accepted for publication in Astrophysics and Space Science

Managers and wage policies

We investigate the effects of individual top managers on wages and wage policies. A large longitudinal administrative dataset from Portugal allows us to match workers,firms and top managers, and follow the movements of the latter across different firms over time. We estimate the role of top manager fixed-effects in determining wages and wage policies, while also accounting for the effect of worker and firm heterogeneity. Our results reveal that top managers have a significant influence on wages, the returns to schooling and tenure, the gender wage gap, and the extent of rent sharing. Further-more, they point to the existence of managerial styles in the setting of wage policies. Finally, we relate worker compensation to observable managerial attributes, and find that returns to schooling tend to be higher in firms led by more educated top executives, while longer-tenured managers appear on average to engage in more rent sharing.Top managers, wage policies, linked worker-firm-manager data.

Split-sideband spectroscopy in slowly modulated optomechanics

Optomechanical coupling between the motion of a mechanical oscillator and a cavity represents a new arena for experimental investigation of quantum effects on the mesoscopic and macroscopic scale.The motional sidebands of the output of a cavity offer ultra-sensitive probes of the dynamics. We introduce a scheme whereby these sidebands split asymmetrically and show how they may be used as experimental diagnostics and signatures of quantum noise limited dynamics. We show split-sidebands with controllable asymmetry occur by simultaneously modulating the light-mechanical coupling $g$ and $\omega_M$ - slowly and out of-phase. Such modulations are generic but already occur in optically trapped set-ups where the equilibrium point of the oscillator is varied cyclically. We analyse recently observed, but overlooked, experimental split-sideband asymmetries; although not yet in the quantum regime, the data suggests that split sideband structures are easily accessible to future experiments

Firm ownership and rent sharing

We analyse - theoretically and empirically - how private versus public ownership of firms affects the degree of rent sharing between firms and their workers. Using a particularly rich linked employer-employee dataset from Portugal, covering a large number of corporate ownership changes across a wide spectrum of economic sectors over more than 20 years, we find a positive relationship between private ownership and rent sharing. Based on our theoretical analysis, this result cannot be explained by private firms being more profit oriented than public ones. However, the result is consistent with privatisation leading to less job security, implying stronger efficiency wage effects.rent sharing; private vs public ownership; panel data