Quantum coherent control of highly multipartite continuous-variable entangled states by tailoring parametric interactions

The generation of continuous-variable multipartite entangled states is important for several protocols of quantum information processing and communication, such as one-way quantum computation or controlled dense coding. In this article we theoretically show that multimode optical parametric oscillators can produce a great variety of such states by an appropriate control of the parametric interaction, what we accomplish by tailoring either the spatio-temporal shape of the pump, or the geometry of the nonlinear medium. Specific examples involving currently available optical parametric oscillators are given, hence showing that our ideas are within reach of present technology.Comment: 14 pages, 5 figure

Strawberry fruit resistance to simulated handling

Harvest operations are currently the main source of mechanical injury of strawberry (Fragaria x ananassa Duch.). Experiments were designed to simulate conditions encountered during commercial handling. Individual fruits were subjected to impact or compression forces with similar energy to determine the sensitivity to mechanical injury. Bruise volume was used as the measurement of injury. Bruise severity increased as a function of impact energy for both impact types. However, dropped fruits had larger bruise volume than fruits submitted to pendulum impactor at the same energy level. Doubling the impact energy (0.040 to 0.083 J) increased bruise volume by 7 times (13 to 91 mm³). Fruits dropped from 380 mm (0.075 J) showed 71% greater bruise volume than those dropped from either 130 mm (0.025 J) or 200 mm (0.040 J). Compressed fruits showed higher bruise volume than other tests. Some cultivars are more susceptible to compression forces than others. 'Sweet Charlie' berries showed bruise volume 40% higher than the others cultivars when subjected to compression. Fruits subjected to impact showed bruise volume lower than the compressed fruits, indicating the possibility to be handled and graded in a packing line.A etapa de colheita é a principal fonte de danos físicos ao morango (Fragaria x ananassa Duch.). Experimentos foram realizados para simular condições encontradas durante manuseio. Frutos foram submetidos individualmente às forças de impacto e compressão em energias similares para determinar sensibilidade dos frutos a danos físicos. Volume da injúria física foi utilizado para mensurar a incidência do dano físico ocorrido. Severidade da lesão aumenta, com incremento da energia, tanto para força de impacto como para compressão. Todavia, frutos submetidos à queda livre demonstraram maiores volumes de danos físicos do que frutos submetidos a danos ocasionados por pendulo no mesmo nível de energia. Dobrando a energia de impacto (0,040 para 0,083 J) ocorreu aumento no volume da injúria em sete vezes (13 para 91 mm³). Frutos submetidos à queda de 380 mm (0,075 J) demonstraram volumes de danos físicos 71% superiores do que aqueles ocasionados em queda de 130 mm (0,025 J) ou 200 mm (0,040 J). Frutos em teste de compressão mostraram maiores volumes de injúrias físicas do que outros testes. Alguns cultivares são mais sensíveis à força de compressão do que outros. Frutos cultivar 'Sweet Charlie' apresentaram volume de injúria 40% superiores do que outros quando submetidos à força de compressão. Morangos submetidos à força de impacto demonstraram volume de injúria inferior do que aqueles comprimidos, indicando a possibilidade dos morangos serem classificados e manuseados em uma linha de beneficiamento

Untersuchungen zur Plasma-Jet-Abscheidung von Diamantschichten Abschlussbericht

Gesamtziel des Projektes waren systematische Untersuchungen zur Verbesserung des Plasma-Jet-Verfahrens hinsichtlich der Zuverlaessigkeit und Produktivitaet. Dazu wurden von den Wissenschaftlern des GPI umfangreiche technologische Untersuchungen zur Modifikation des Plasmatrons durchgefuehrt. Zum einen konnte die Lebensdauer des Plasmatrons erheblich gesteigert und der Arbeitsdruck- und Leistungsbereich erweitert werden. Zum anderen konnten wichtige Ergebnisse im Hinblick auf eine reinere Schicht, eine hoehere Depositionsrate, und eine groessere beschichtete Flaeche erreicht werden. Auch wurde eine Laserablationsanlage zur Diamantschichtglaettung/-strukturierung aufgebaut. Mit dieser Anlage konnte erfolgreich gezeigt werden, dass mit der Laserablation eing eeignetes Verfahren zur Verfuegung steht, um die mit dem Plasma-Jet-Verfahren abgeschiedenen Diamantschichten fuer diverse Anwendungen zu glaetten und zu strukturieren. Dabei wurde der Nachweis erbracht, dass sich dieses Verfahren auch fuer grossflaechige Bearbeitung von Diamantschichten eignet. (orig.)The aim of this project was the systematic investigation of the plasma-jet CVD process for improvement of its reliability and productivity. The scientists from the General Physics Institute Moscow have performed extensive investigations and modifications of the plasmatron. On this the lifetime of the plasmatron could be increased and the range of work pressure and efficiency have been extended. Additionally important results particularly with regard to pure diamond films with high quality, higher deposition rate and increased deposition area could be achieved. Furthermore a device for ablative laser smoothing and structuring of diamond films was built. With this new set-up the efficiency of laser smoothing and structuring of plasma-jet synthesised diamond films for special applications was demonstrated. The developed system can also be used for large area treatment of diamond films. (orig.)SIGLEAvailable from TIB Hannover: F01B1327+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman