New Data on the Genus Sucinoptius (Coleoptera, Ptinidae) from Rovno Amber

Study of five examples of spider beetle inclusions from Rovno amber revealed that at least three of these spider beetles belong to the genus Sucinoptinus Bellés et Vitali, 2007, of them, S. rovnoensis sp. n. (most probably from Klesov) and S. brevipennis sp. n. from Dubrovitsa are described. S. rovnoensis is similar to the previously known S. bukejsi Alekseev in having the same general structure of pronotum and elytra, differing from it by the morphology of pronotal sides, which are only slightly rounded and practically not constricted near the base, whereas in S. bukejsi the sides are well rounded leaving a slight but clear constriction near the base. S. brevipennis is similar to S. bukejsi Alekseev and S. sucini Bellés et Vitali in having the same general structure of the prothorax, but differing from them in having much shorter elytra. Addition of these two new species to the two previously known, S. sucini, from the eastern Baltic Sea coast, and S. bukejsi, from Kaliningrad Region, indicates that the genus Sucinoptinus was much more diverse and widespread in Late Eocene forests than former reports suggested.Peer reviewe

Constructing finite dimensional codes with optical continuous variables

We show how a qubit can be fault-tolerantly encoded in the infinite-dimensional Hilbert space of an optical mode. The scheme is efficient and realizable with present technologies. In fact, it involves two travelling optical modes coupled by a cross-Kerr interaction, initially prepared in coherent states, one of which is much more intense than the other. At the exit of the Kerr medium, the weak mode is subject to a homodyne measurement and a quantum codeword is conditionally generated in the quantum fluctuations of the intense mode.Comment: 7 pages, 5 figure

Quantum 2-Body Hamiltonian for Topological Color Codes

We introduce a two-body quantum Hamiltonian model with spins-\half located on the vertices of a 2D spatial lattice. The model exhibits an exact topological degeneracy in all coupling regimes. This is a remarkable non-perturbative effect. The model has a $\Z_2\times \Z_2$ gauge group symmetry and string-net integrals of motion. There exists a gapped phase in which the low-energy sector reproduces an effective topological color code model. High energy excitations fall into three families of anyonic fermions that turn out to be strongly interacting. All these, and more, are new features not present in honeycomb lattice models like Kitaev model.Comment: Cotribution to the Proceedings of the Scala Conference 2009 (Cortina, Italy). Special Issue dedicated to Prof. Prof. Tombesi, on occasion of his seventieth birthday. Editors: D. Vitali, I Marzoli, S. Mancini, G. Di Giuseppe. "Fortschritte der Physik

A model independent approach to non dissipative decoherence

We consider the case when decoherence is due to the fluctuations of some classical variable or parameter of a system and not to its entanglement with the environment. Under few and quite general assumptions, we derive a model-independent formalism for this non-dissipative decoherence, and we apply it to explain the decoherence observed in some recent experiments in cavity QED and on trapped ions.Comment: 12 pages, 3 figure

Robust entanglement of a micromechanical resonator with output optical fields

We perform an analysis of the optomechanical entanglement between the experimentally detectable output field of an optical cavity and a vibrating cavity end-mirror. We show that by a proper choice of the readout (mainly by a proper choice of detection bandwidth) one can not only detect the already predicted intracavity entanglement but also optimize and increase it. This entanglement is explained as being generated by a scattering process owing to which strong quantum correlations between the mirror and the optical Stokes sideband are created. All-optical entanglement between scattered sidebands is also predicted and it is shown that the mechanical resonator and the two sideband modes form a fully tripartite-entangled system capable of providing practicable and robust solutions for continuous variable quantum communication protocols

Wear rates in urban rail systems

A significant part of maintenance costs in urban rail systems (metro, tram, light rapid transit/light metro) is due to wheel-rail wear. Wear rates - measured for example as depth of wear per kilometre run (rolling stock) or per train passage (rails) - depend in a complex manner on several influence factors. Among the most important are key design factors of the rolling stock (wheel profiles, suspension characteristics), of the track (distribution of curve radii, characteristics of switches and crossings, rail profiles), of the wheel-rail interface (lubrication, materials in contact, ambient characteristics), and of operations (frequency of traction and braking, trainset inversion policy, maintenance policy etc.). When designing an urban rail system, all of these factors have to be under control in order to limit the costs due to wheel/rail reprofiling/grinding and replacement. The state of the art allows the calculation of wear rates given quantitative input regarding the above factors. However, it is difficult to find in the literature experimental values for calibration of wear models and indications on what is a reasonable state-of-the-art wear rate for any given type of urban rail system. In this paper we present a structured analysis of flange wear rates found in the literature and derived from the experience of the authors, for a variety of cases, including metros and mainline rail systems. We compare the wear rates and explain their relationship with the influence factors. We then relate the wear rates with the needs in terms of wheel reprofiling/replacement. We estimate ranges for the calibration coefficients of wear models. We present the results in a way as to allow the designer of urban rail systems to derive values for target wear rates according to their specific conditions without the need for complex simulations