LOCC distinguishability of unilaterally transformable quantum states

We consider the question of perfect local distinguishability of mutually orthogonal bipartite quantum states, with the property that every state can be specified by a unitary operator acting on the local Hilbert space of Bob. We show that if the states can be exactly discriminated by one-way LOCC where Alice goes first, then the unitary operators can also be perfectly distinguished by an orthogonal measurement on Bob's Hilbert space. We give examples of sets of N<=d maximally entangled states in $d \otimes d$ for d=4,5,6 that are not perfectly distinguishable by one-way LOCC. Interestingly for d=5,6 our examples consist of four and five states respectively. We conjecture that these states cannot be perfectly discriminated by two-way LOCC.Comment: Revised version, new proofs added; to appear in New Journal of Physic

On Property (FA) for wreath products

We characterize permutational wreath products with Property (FA). For instance, the standard wreath product A wr B of two nontrivial countable groups A,B, has Property (FA) if and only if B has Property (FA) and A is a finitely generated group with finite abelianisation. We also prove an analogous result for hereditary Property (FA). On the other hand, we prove that many wreath products with hereditary Property (FA) are not quotients of finitely presented groups with the same property.Comment: 12 pages, 0 figur

Characteristics of cloud-to-ground lightning activity over Seoul, South Korea in relation to an urban effect

Cloud-to-ground (CG) lightning flash data collected by the lightning detection network installed at the Korean Meteorological Administration (KMA) have been used to study the urban effect on lightning activity over and around Seoul, the largest metropolitan city of South Korea, for the period of 1989&amp;ndash;1999. Negative and positive flash density and the percentage of positive flashes have been calculated. Calculation reveals that an enhancement of approximately 60% and 42% are observed, respectively, for negative and positive flash density over and downwind of the city. The percentage decrease of positive flashes occurs over and downwind of Seoul and the amount of decrease is nearly 20% compared to upwind values. The results are in good agreement with those obtained by Steiger et al. (2002) and Westcott (1995). CG lightning activities have also been considered in relation to annual averages of PM&lt;sub&gt;10&lt;/sub&gt; (particulate matter with an aerodynamic diameter smaller than 10 μm) and sulphur dioxide (SO&lt;sub&gt;2&lt;/sub&gt;) concentrations. Interesting results are found, indicating that the higher concentration of SO&lt;sub&gt;2&lt;/sub&gt; contributes to the enhancement of CG lightning flashes. On the other hand, the contribution from PM&lt;sub&gt;10&lt;/sub&gt; concentration has not appeared in this study to be as significant as SO&lt;sub&gt;2&lt;/sub&gt; in the enhancement of CG lightning flashes. Correlation coefficients of 0.33 and 0.64 are found between the change in CG lightning flashes and the PM&lt;sub&gt;10&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt;, respectively, for upwind to downwind areas, suggesting a significant influence of the increased concentration of SO&lt;sub&gt;2&lt;/sub&gt; on the enhancement of CG flashes

Observation of Confinement-Induced Self-Poling Effects in Ferroelectric Polymer Nanowires Grown by Template Wetting

Ferroelectric polymer nanowires grown using a template-wetting method are shown to achieve an orientated 'self-poled' structure resulting from the confined growth process. Self-poling is highly desirable as it negates the need for high electric fields, mechanical stretching and/or high temperatures typically associated with poling treatments in ferroelectric polymers, as required for piezoelectric and/or pyroelectric applications. Here, we present differential scanning calorimetry, infrared spectroscopy and dielectric permittivity measurements on as-fabricated template-grown polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)) nanowires, and quantitatively compare the results with spin-cast films of the same composition that have been electrically poled, both before and after subsequent de-poling temperature treatment. The measurements reveal remarkably similar trends between the physical properties of the as-grown nanowires and the electrically poled film samples, providing insight into the material structure of the 'self-poled' nanowires. In addition, piezo-response force microscopy (PFM) data is presented that allow s for unambiguous identification of self-poling in ferroelectric polymer nanostructures, and indicates the suitability of the template-wetting approach in fabricating nanowires that can be used directly for piezoelectric/pyroelectric applications, without the need for post-deposition poling/processing.The authors are grateful for financial support from the European Research Council through an ERC Starting Grant (Grant no. ERC-2014-STG-639526, NANOGEN). R.A.W. thanks the EPSRC Cambridge NanoDTC, EP/G037221/1, for studentship funding.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Wiley

A Decision Support System for Market Segmentation - A Neural Networks Approach

Market segmentation refers to the subdividing of a market into distinct subsets of customers where any subset may conceivably be selected as a market target to be reached with a distinct marketing mix [Kotler 1980]. The reason for segmenting a market is that consumers are often numerous, geographically dispersed, and heterogeneous, and therefore seek varying benefits from the products they buy. Consumers within a segment are expected to have homogeneous buying preferences whereas those in different segments tend to behave differently. By properly identifying the benefit segment of a firm\u27s product, the marketing manager can target the sales effort at specific groups of consumers rather than at the total population. The identification of consumer segments is of critical importance for key strategic issues in marketing involving the assessment of a firm\u27s opportunities and threats. The marketing manager must evaluate the potential of the firm\u27s products in the target segment and ultimately select the most promising strategy for the segment. In thisresearch, we introduce a new approach, a neural networks based method, to discover market segments and configure them into meaningful structures. The particular type of neural networks, the Self-Organizing Map networks, can be used as a decision support tool for supporting strategic decisions involving identifying and targeting market segments. The Self-Organizing Map (SOM) network, a variation of neural computing networks, is a categorization network developed by Kohonen. The theory of the SOM network is motivated by the observation of the operation of the brain. This paper presents the technique of SOM and shows how it may be applied as a clustering tool to market segmentation. A computer program for implementing the SOM neural networks is developed and the results will be compared with other clustering approaches. The study demonstrates the potential of using the Self-Organizing Map as the clustering tool for market segmentation

Piezoelectric Semiconducting Nanowires

© 2018 Elsevier Inc. Piezoelectric semiconducting nanowires have generated much interest due to the interplay of their mechanical, electrical, and optical properties, which paves the way for potential applications in mechanical energy harvesting as well as sensing. The nature of piezoelectricity in these nanowires is governed by the crystalline phases present, which in turn can be controlled during the nanowire growth process. This chapter provides insight into the manifestation of piezoelectricity in semiconducting nanowires, the effect of growth on their piezoelectric properties, and importantly, how piezoelectricity is characterized at the nanoscale in these materials. Energy-related applications of semiconducting piezoelectric nanowires are described in detail, including their incorporation into nanogenerators for energy harvesting, as well as in piezotronic and photo-piezotronics devices based on the electromechanical and opto-electromechanical interactions taking place in piezoelectric semiconductor-nanowire junction-based devices. Advances in nanofabrication, nanoscale characterization, and device engineering, coupled with a greater understanding and control of piezoelectricity in semiconducting nanowires, will ultimately help unlock the full potential of these fascinating nanomaterials.European Research Council (Grant no. ERC–2014–STG–639526, NANOGEN

First evidence of predation of the ant species lasius alienus on the poultry red mite dermanyssus gallinae

The poultry red mite (PRM), Dermanyssus gallinae (De Geer, 1778) (Acari: Dermanyssi-dae), is a common and significant ectoparasite of the poultry industry worldwide. Although various biological, chemical, and physical methods have been attempted, an utterly successful control strategy has not been put forward yet. Our experimental investigations and observations revealed that the ant species Lasius alienus displays an effective predatory behavior on all biological stages of PRM. Our results also suggested that L. alienus is attracted by PRM­infested substrate at a distance. We concluded that predation by the ant on PRM is worth further investigation as it could possibly be an effective biological control strategy. © Kar S. et al

Localized electromechanical interactions in ferroelectric P(VDF-TrFE) nanowires investigated by scanning probe microscopy

We investigate the electromechanical interactions in individual polyvinylidene fluoride-trifluoroethylene nanowires in response to localized electrical poling via a conducting atomic force microscope tip. Spatially resolved measurements of piezoelectric coefficients and elastic moduli before and after poling reveal a striking dependence on the polarity of the poling field, notably absent in thin films of the same composition. These observations are attributed to the unclamped nature of the nanowires and the inherent asymmetry in their chemical and electrical interactions with the tip and underlying substrate. Our findings provide insights into the mechanism of poling/switching in polymer nanowires critical to ferroelectric device performance.S.K.-N. and Y.C. are grateful for financial support from the European Research Council through an ERC Starting Grant (Grant No. ERC-2014-STG-639526, NANOGEN). R.A.W. thanks the EPSRC Cambridge NanoDTC, EP/G037221/1, for studentship funding. Q.J. is grateful for financial support through a Marie Sklodowska Curie Fellowship, H2020-MSCA-IF-2015-702868