Maximally Entangled Mixed-State Generation via Local Operations

We present a general theoretical method to generate maximally entangled mixed states of a pair of photons initially prepared in the singlet polarization state. This method requires only local operations upon a single photon of the pair and exploits spatial degrees of freedom to induce decoherence. We report also experimental confirmation of these theoretical results.Comment: 5 pages, 2 figures, to be published in Physical Review

Parametric studies of advanced turboprops

The effects of geometric variables (sweep and twist) on the structural performance of advanced turboprops are investigated. The investigation is limited to aerodynamically efficient turboprops using an acceptable design configuration as a baseline. The baseline configuration is modified using a seven by seven array of independently varying sweep and twist parameters while maintaining acceptable aerodynamic efficiency. The turboprop structural performance is evaluated in terms of critical speeds, tip displacements, and vibration frequencies where geometric nonlinearities are included. The results obtained are presented in such a manner as to highlight the effects of sweep and twist on the structural performance of aerodynamically efficient turboprop configurations

Angular spectrum of quantized light beams

We introduce a generalized angular spectrum representation for quantized light beams. By using our formalism, we are able to derive simple expressions for the electromagnetic vector potential operator in the case of: {a)} time-independent paraxial fields, {b)} time-dependent paraxial fields, and {c)} non-paraxial fields. For the first case, the well known paraxial results are fully recovered.Comment: 3 pages, no figure

Natural convection cooling of a hot vertical wall wet by a falling liquid film

The system studied is a plane channel delimited by two vertical walls, one of which is imposed an arbitrary temperature profile and may be partially or totally wet by a liquid film, while the other is adiabatic. Air from the environment flows along the channel, driven by buoyancy forces. Its mass flow rate depends on the hydraulic resistances and on the distribution of temperature and humidity (hence, density) along the channel, which, in turn, depends on the heat and mass transfer between hot wall and humid air. Due to evaporative or boiling mass transfer, the liquid film, if present, shrinks as it descends along the hot wall, and may be completely dried out at some height. A simplified computational model of the above system was developed and applied to the prediction of relevant quantities, such as the total energy subtracted to the hot wall, for a range of conditions (hot wall temperature and its distribution; film flow rate; ambient air temperature and humidity; channel height and thickness; localized hydraulic resistance)

vibration mitigation of a linear host structure using a passive neutralizer effect of nonlinearity in the neutralizer suspension

Abstract Motivated by some experimental results on a test-rig, this paper presents some observations on the frequency response of a primary linear oscillator when an auxiliary nonlinear oscillator is attached to it, acting as a vibration neutralizer. In the experiments, an electro-dynamic shaker is used as the linear one-degree-of-freedom primary oscillator, and it is excited by an harmonic force. The nonlinear neutralizer is attached to the moving head of the shaker, and it is assembled to achieve a cubic stiffness characteristics, due to geometrical arrangement of linear elastic elements. For very low vibration amplitudes, the whole system behaves predominantly as a two-degree-of-freedom linear oscillator, but when the force excitation to the shaker is increased the shape of the frequency response curve changes, and exhibits resonance peak bending, jump phenomena and instabilities of the harmonic response. A theoretical model of the system is presented, with the aim to capture the qualitative phenomena observed in the experiments

A NASTRAN primer for the analysis of rotating flexible blades

This primer provides documentation for using MSC NASTRAN in analyzing rotating flexible blades. The analysis of these blades includes geometrically nonlinear (large displacement) analysis under centrifugal loading, and frequency and mode shape (normal modes) determination. The geometrically nonlinear analysis using NASTRAN Solution sequence 64 is discussed along with the determination of frequencies and mode shapes using Solution Sequence 63. A sample problem with the complete NASTRAN input data is included. Items unique to rotating blade analyses, such as setting angle and centrifugal softening effects are emphasized

Random graph model with power-law distributed triangle subgraphs

Clustering is well-known to play a prominent role in the description and understanding of complex networks, and a large spectrum of tools and ideas have been introduced to this end. In particular, it has been recognized that the abundance of small subgraphs is important. Here, we study the arrangement of triangles in a model for scale-free random graphs and determine the asymptotic behavior of the clustering coefficient, the average number of triangles, as well as the number of triangles attached to the vertex of maximum degree. We prove that triangles are power-law distributed among vertices and characterized by both vertex and edge coagulation when the degree exponent satisfies $2<\beta<2.5$; furthermore, a finite density of triangles appears as $\beta=2+1/3$.Comment: 4 pages, 2 figure; v2: major conceptual change

Searching in Unstructured Overlays Using Local Knowledge and Gossip

This paper analyzes a class of dissemination algorithms for the discovery of distributed contents in Peer-to-Peer unstructured overlay networks. The algorithms are a mix of protocols employing local knowledge of peers' neighborhood and gossip. By tuning the gossip probability and the depth k of the k-neighborhood of which nodes have information, we obtain different dissemination protocols employed in literature over unstructured P2P overlays. The provided analysis and simulation results confirm that, when properly configured, these schemes represent a viable approach to build effective P2P resource discovery in large-scale, dynamic distributed systems.Comment: A revised version of the paper appears in Proc. of the 5th International Workshop on Complex Networks (CompleNet 2014) - Studies in Computational Intelligence Series, Springer-Verlag, Bologna (Italy), March 201