Sub-shot-noise heterodyne polarimetry

We report an experimental demonstration of a heterodyne polarization rotation measurement with a noise floor 4.8 dB below the optical shot noise by use of classically phase-locked quantum twin beams emitted above threshold by an ultrastable type II Na:KTP cw optical parametric oscillator. We believe that this is the largest noise reduction achieved to date in optical phase-difference measurements.     

A new two-chip concept for continuous measurements on PMMA-microchips

A new concept for continuous measurements on microchips is presented. A PMMA (polymethylmethacrylate) based capillary electrophoresis chip with integrated conductivity detection is combined with a second chip, which undertakes the task of fluid handling and electrical connections. The combination of electrokinetic and hydrodynamic flows allows long-term continuous stable analyses with good reproducibilities of migration time and peak heights of analytes. The two-chip system is characterized in terms of stability and reproducibility of separation and detection of small ions. Relative standard deviations of <1% and 3% respectively for retention times and peak heights during long-term measurements can be achieved. The new system combines simple handling and automated analysis without the need for refilling, cleaning or removal of the separation chip after one or several measurements.     

SEM and photoluminescence study of Li segregation in annealed zinc telluride

We report luminescence spectra with spatial and spectral resolution which show the predominant effect of lithium on optical and electrical properties of annealed ZnTe. Lithium is identified in photoluminescence spectra at 5 K whereas SEM visualizes the diffusion of this impurity. We can also observe the effect of high impurity concentration of luminescence with the apparition of excitons bound to LiLi pairs.     

Über eine Art von gemischter Topologie und einen Satz von A. Grothendieck über (DF)-Räume

Let E be a real or complex linear space, s and t linear topologies on E, ts. We define some kind of mixed topology m(s, t) such that tm(s, t)s. The linear topology m(s, t) is characterized by a theorem of Banach-Steinhaus type and we show that the condition t=m(s, t) covers various concepts of barrelledness. Secondly we show that s and m(s, t) induce the same uniformity on certain subsets of E, if there is a base of s-neighbourhoods of O which are t-closed; this theorem will be a generalization of a well known theorem of A. Grothendieck on (DF)-spaces.     

Electrical and optical identification of the persistent acceptor as copper in ZnTe

Capacitance, photoluminescence and infra-red absorption experiments have been performed on copper doped ZnTe single crystals. Comparative measurements on samples treated at various temperatures show clearly that Cu introduces a single acceptor level with high solubility. Spectroscopic results allow to identify the persistent acceptor “a” at 149 meV as copper on substitutional zinc site confirming that native defects are not responsible for the p-type conductivity of undoped ZnTe.     

Isolated Newtonian Dust Stars Are Unstable But Can Be Stabilized by Exterior Matter

The mathematical problem of the existence of solutions for Newtonian dust stars is formulated, and proofs for the non-existence of such stars as isolated objects are given. It is however shown that such stars can be stabilized by reasonable exterior (strained) matter. Comments are made on the problem of Einsteinian rotating dust stars.     

OptiDose: Computing the Individualized Optimal Drug Dosing Regimen Using Optimal Control

Journal of Optimization Theory and Applications - Providing the optimal dosing strategy of a drug for an individual patient is an important task in pharmaceutical sciences and daily clinical...     

Classical spin systems in the presence of a wall: Multicomponent spins

In this paper we investigate classical spin systems on a semi-infinite lattice. We establish detailed properties of such systems near the surface layer. For the Ising- and the classicalXY models on a semi-infinite lattice we study the phase diagram, the critical properties and the decay of spin-spin correlations near the surface layer.