Privatization Incentives – A Wage Bargaining Approach

We analyze the incentives of a government to privatize a state owned firm. Assumingprice cap regulation, a unionized labor market and wage bargaining the government’sgains from privatization depend on two effects. While the government looses controlover the firm’s investment and employment decisions, the union’s bargaining positioncan be weakened by privatization. Since price cap regulation tends to increase the wage under privatization, the government’s incentives to privatize are low if the union’s bargaining power is high. Considering different kinds of in-vestments does not change this result qualitatively.Wage bargaining regulation privatization

Transform-limited single photons from a single quantum dot

A semiconductor quantum dot mimics a two-level atom. Performance as a single photon source is limited by decoherence and dephasing of the optical transition. Even with high quality material at low temperature, the optical linewidths are a factor of two larger than the transform-limit. A major contributor to the inhomogeneous linewdith is the nuclear spin noise. We show here that the nuclear spin noise depends on optical excitation, increasing (decreasing) with increasing resonant laser power for the neutral (charged) exciton. Based on this observation, we discover regimes where we demonstrate transform-limited linewidths on both neutral and charged excitons even when the measurement is performed very slowly

Structural Stability: On the Prerequisites of Nonviolent Conflict Management

The concept of “structural stability” has been gaining prominence in development policy circles. In the EU’s and the OECD Development Assistance Committee’s (OECD DAC) understanding, it describes the ability of societies to handle intra-societal conflict without resorting to violence. This study investigates the preconditions of structural stability and tests their mutual interconnections. Seven dimensions are analyzed: (1) long-term economic growth, (2) environmental security, (3) social equality, (4) governmental effectiveness, (5) democracy, (6) rule of law, and (7) inclusion of identity groups. The postulated mutual enhancement of the seven dimensions is plausible but cannot be proven. The most significant positive relationship appears between “democracy” and “rule of law,” respectively, on the one hand and the dependent variable “violence/ human security” on the other hand. This points to the usefulness of the political concept of structural stability to promote development policy agendas in this area at least. Applications that reach beyond these initial findings will, however, require further research.Structural stability, violence, human security, development aid, conflict management, prerequisites of nonviolence

Epitaxial lift-off for solid-state cavity quantum electrodynamics

We present a new approach to incorporate self-assembled quantum dots into a Fabry-P\'{e}rot-like microcavity. Thereby a 3$\lambda$/4 GaAs layer containing quantum dots is epitaxially removed and attached by van der Waals bonding to one of the microcavity mirrors. We reach a finesse as high as 4,100 with this configuration limited by the reflectivity of the dielectric mirrors and not by scattering at the semiconductor - mirror interface, demonstrating that the epitaxial lift-off procedure is a promising procedure for cavity quantum electrodynamics in the solid state. As a first step in this direction, we demonstrate a clear cavity-quantum dot interaction in the weak coupling regime with a Purcell factor in the order of 3. Estimations of the coupling strength via the Purcell factor suggests that we are close to the strong coupling regime.Comment: 6 pages, 4 figure

Electrically-tunable hole g-factor of an optically-active quantum dot for fast spin rotations

We report a large g-factor tunability of a single hole spin in an InGaAs quantum dot via an electric field. The magnetic field lies in the in-plane direction x, the direction required for a coherent hole spin. The electrical field lies along the growth direction z and is changed over a large range, 100 kV/cm. Both electron and hole g-factors are determined by high resolution laser spectroscopy with resonance fluorescence detection. This, along with the low electrical-noise environment, gives very high quality experimental results. The hole g-factor g_xh depends linearly on the electric field Fz, dg_xh/dFz = (8.3 +/- 1.2)* 10^-4 cm/kV, whereas the electron g-factor g_xe is independent of electric field, dg_xe/dFz = (0.1 +/- 0.3)* 10^-4 cm/kV (results averaged over a number of quantum dots). The dependence of g_xh on Fz is well reproduced by a 4x4 k.p model demonstrating that the electric field sensitivity arises from a combination of soft hole confining potential, an In concentration gradient and a strong dependence of material parameters on In concentration. The electric field sensitivity of the hole spin can be exploited for electrically-driven hole spin rotations via the g-tensor modulation technique and based on these results, a hole spin coupling as large as ~ 1 GHz is expected to be envisaged.Comment: 8 pages, 4 figure

The Tree-Generative Capacity of Combinatory Categorial Grammars

The generative capacity of combinatory categorial grammars as acceptors of tree languages is investigated. It is demonstrated that the such obtained tree languages can also be generated by simple monadic context-free tree grammars. However, the subclass of pure combinatory categorial grammars cannot even accept all regular tree languages. Additionally, the tree languages accepted by combinatory categorial grammars with limited rule degrees are characterized: If only application rules are allowed, then they can accept only a proper subset of the regular tree languages, whereas they can accept exactly the regular tree languages once first degree composition rules are permitted