Exciton polaritons confined in a ZnO nanowire cavity

Semiconductor nanowires of high purity and crystallinity hold promise as building blocks for miniaturized optoelectrical devices. Using scanning-excitation single-wire emission spectroscopy, with either a laser or an electron beam as a spatially resolved excitation source, we observe standing-wave exciton polaritons in ZnO nanowires at room temperature. The Rabi splitting between the polariton branches is more than 100 meV. The dispersion curve of the modes in the nanowire is substantially modified due to light-matter interaction. This finding forms a key aspect in understanding subwavelength guiding in these nanowires.     

Visualizing the whispering gallery modes in a cylindrical optical microcavity

Whispering gallery modes in cylindrical integrated optics microcavities have, for what is to our knowledge the first time, been mapped with a photon scanning tunneling microscope. Optical images were obtained with a spatial resolution of 50 nm. By combination of information on the spatial optical distributions with wavelength-dependent measurements, an unexpectedly rich variety of intracavity phenomena, such as polarization conversion and interference of copropagating and counterpropagating modes, could be directly observed. A quantitative comparison of the experimental data with computer simulations results in a comprehensive understanding of the various whispering gallery modes inside the microcavity.     

Tweaking copper hydride (CuH) for synthetic gain. A practical,one-pot conversion of dialkyl ketones to reduced trialkylsilyl ether derivatives

[reaction: see text] Variations in the reagents and stoichiometries used to generate CuH in situ, as well as the nature of the ligands present, have led to a very efficient and inexpensive method for effecting hydrosilylations of dialkyl ketones.     

Bin packing games

We consider bin packing games introduced by Faigle and Kern (1993) and we restrict ourselves to the subclass of games for which all bins have unit capacity and all items are larger than 1/3. We adopt the taxation model of Faigle and Kern and we prove that for a tax-rate of = sk_7/1 the -core is always non empty. The bound is sharp, since for every < sk_7/1 there exist instances of the bin packing game within our sublass with an empty -core.     

An axiomatic approach to egalitarianism in TU-games

A core concept is a solution concept on the class of balanced games that exclusively selects core allocations. We show that every continuous core concept that satisfies both the equal treatment property and a new property called independence of irrelevant core allocations (IIC) necessarily selects egalitarian allocations. IIC requires that, if the core concept selects a certain core allocation for a given game, and this allocation is still a core allocation for a new game with a core that is contained in the core of the first game, then the core concept also chooses this allocation as the solution to the new game. When we replace the continuity requirement by a weak version of additivity we obtain an axiomatization of the egalitarian solution concept that assigns to each balanced game the core allocation minimizing the Euclidean distance to the equal share allocation.