2,898 research outputs found
Topological Open String Amplitudes On Orientifolds
We study topological open string amplitudes on orientifolds without fixed
planes. We determine the contributions of the untwisted and twisted sectors as
well as the BPS structure of the amplitudes. We illustrate our general results
in various examples involving D-branes in toric orientifolds. We perform the
computations by using both the topological vertex and unoriented localization.
We also present an application of our results to the BPS structure of the
coloured Kauffman polynomial of knots.Comment: 43 pages, 8 figure
Why the Book of Revelation?
In lieu of an abstract, below is the essay\u27s first paragraph.
Have you ever thought about how the Book of Revelation came to be included into the New Testament canon? It may not seem like that big of a deal, but when we take a closer look throughout history we see that it gained entrance over numerous other apocalypses. This is especially critical for the type of book that it is, as it concerns the end of the world and the fate of humanity
New Testament Biblical Apocrypha and the Exclusion of Apocalypses from the Canon
In lieu of an abstract, below is the essay\u27s first paragraph.
The criteria for canonicity which led to the inclusion of the Book of Revelation in the New Testament call into question the exclusion of other apocryphal apocalypses and revelatory treatises. Biblical apocrypha is defined as texts that were at one time a part of the biblical canon but no longer are, or texts that were never a part of the biblical canon at all but are widely known and valued. Examples of writings that collectively make up the apocrypha are gospels, gnostic texts, acts, epistles, apocalypses, fragments, lost works, and other miscellaneous texts
Cross-Selectivity in the Catalytic Ketonization of Carboxylic Acids
A mixture of acetic and 2-methylpropanoic (isobutyric) acids representing non-branched and branched acids, respectively, was catalytically converted to a mixture of ketones in a set of statistically designed experiments (DOE). The selectivity toward the cross-ketonization product was analyzed depending on (a) temperature within 300–450 °C range, (b) molar fraction of each acid in the mixture, from 10% to 90%, and (c) liquid hourly space velocity (LHSV) within 2–12 h−1, and compared against the selectivity toward two symmetrical ketones. Six metal oxide catalysts were tested and ranked on their ability to yield the cross-product as opposed to the self-condensation product. The catalysts were based on either the anatase form of titania or monoclinic form of zirconia and treated with either KOH or K2HPO4. The titania catalyst treated by KOH outperformed all other catalysts by providing the cross-selectivity above the statistically expected binomial distribution. The criterion for having a high cross-selectivity in the decarboxylative ketonization is formulated mathematically as the separation of roles of two acids, one being a more active enolic component, and the other being the preferred carbonyl component. According to the suggested criterion, the less branched acetic acid reacts as both the preferred carbonyl and enolic component with untreated catalysts. Therefore, untreated catalysts promote selective formation of the symmetrical ketone, acetone, thereby decreasing the selectivity to the cross-ketone. After alkaline treatment, both the anatase form of titania and monoclinic form of zirconia increase the isobutyric acid participation as the carbonyl component. Acetic acid remains as the preferred enolic component with all treated catalysts, thus increasing the selectivity toward the cross-product in the ketonization of a mixture of carboxylic acids. The condition for achieving a high cross-selectivity by polarizing roles of the two reactants can be extended to other types of cross-condensations
Squeezed Light and Entangled Images from Four-Wave-Mixing in Hot Rubidium Vapor
Entangled multi-spatial-mode fields have interesting applications in quantum
information, such as parallel quantum information protocols, quantum computing,
and quantum imaging. We study the use of a nondegenerate four-wave mixing
process in rubidium vapor at 795 nm to demonstrate generation of
quantum-entangled images. Owing to the lack of an optical resonator cavity, the
four-wave mixing scheme generates inherently multi-spatial-mode output fields.
We have verified the presence of entanglement between the multi-mode beams by
analyzing the amplitude difference and the phase sum noise using a dual
homodyne detection scheme, measuring more than 4 dB of squeezing in both cases.
This paper will discuss the quantum properties of amplifiers based on
four-wave-mixing, along with the multi mode properties of such devices.Comment: 11 pages, 8 figures. SPIE Optics and Photonics 2008 proceeding (San
Diego, CA
Low-Noise Amplification of a Continuous Variable Quantum State
We present an experimental realization of a low-noise, phase-insensitive
optical amplifier using a four-wave mixing interaction in hot Rb vapor.
Performance near the quantum limit for a range of amplifier gains, including
near unity, can be achieved. Such low-noise amplifiers are essential for
so-called quantum cloning machines and are useful in quantum information
protocols. We demonstrate that amplification and ``cloning'' of one half of a
two-mode squeezed state is possible while preserving entanglement.Comment: To appear in Physical Review Letters July 3rd. 4 pages, 4 figure
Technological aspects of an erly 19th c. English and French white earthenware assemblage from Bern (Switzerland)
Composition and technology of 18th century high magnesia faïences from Fulda
In 1996, archaeological excavations close to the ancient Fulda faïence manufacture site unearthed a rich deposit of faïence wastes (biscuits, faïences, technical ceramics). The manufacture was founded in 1741 by Prince Abbot Amand von Buseck and closed down in 1761. This first archaeometric study of a German faïence manufacture included 31 samples produced between 1742 and 1760. Analytical techniques were optical microscopy, X-ray fluorescence, X-ray diffraction and scanning electron microscopy, coupled to an energy-dispersive X-ray spectrometer. Biscuits and faïences are MgO- (5–13 wt.%) and CaO-rich (9–20 wt.%), easily distinguishable from the two French Mg-rich productions of Granges-le-Bourg and Lunéville that we know today. Three samples show high P₂O₅ (2.6–3.3 wt.%). Such unusual concentrations are not due to the admixing of crushed bones to the clay during processing, or to one of the well-known post-firing secondary contamination processes, but are caused by the presence of sharp edged, rhomboedric grains with sizes around 20–30 μm and an overall chemical composition of apatite. These fragments are interpreted to be remnants of primary phosphoritic elements, present ab initium in the clay, and give some hints as to the origin of the raw materials used. Phosphoritic layers can be found in the German Trias, mostly in dolomitic marls of the Middle Keuper. Such marls form the basement on which Fulda is built and could easily have been extracted by the Fulda manufacture. The high MgO values of the faïences can therefore be linked to the presence of dolomitic grains in the plastic raw material, corroborated by the positive MgO/CaO correlation. Firing temperatures of the faïences were, according to their XRD patterns, mostly between 950 and 1050 °C
Archaeometrical study (petrography, mineralogy and chemistry) of Neolithic ceramics from Arbon Bleiche 3 (Canton of Thurgau, Switzerland)
Le but de ce travail de doctorat a été d’étudier en détail les objets archéologiques mis à jour sur le site lacustre de Arbon Bleiche 3, village néolithique situé sur la rive Sud du lac de Constance (Suisse). Entre 1993 et 1995, le service archéologique du canton de Thurgovie a fouillé un périmètre de 1100 m2 (Leuzinger, 2000). La particularité de ce village est d’avoir été occupé pendant une très courte période (15 ans, entre 3384 et 3370 av. J.-C.), durant la période chronologique qui sépare la culture de Pfyn (3900- 3600 av. J.-C.) de celle de Horgen (3200-2800 av. J.- C.), période assez mal documentée en Suisse. La Dr. A. De Capitani a étudié le matériel céramique du site. Elle y observe des caractères des traditions Pfyn et Horgen. Les céramiques sont classées d’après leur affinités typologiques: les pots à caractéristiques Pfyn / Horgen sont séparés des formes spéciales, divisées en quatre sous-groupes: formes spéciales Pfyn (caractéristiques de la culture de Pfyn), formes spéciales Bayern (en relation avec les cultures de Altheim et Cham de Bavière), formes spéciales Boleráz (liées à l’étage Boleráz de la culture de Baden dans la partie ouest du Bassin des Carpates) et les formes spéciales indéterminées. De Capitani (2002) propose une origine locale pour les pots Pfyn / Horgen et pour les formes spéciales Pfyn. Un import de céramiques depuis l’Allemagne ou le Bassin des Carpates étant probable, le but de ce doctorat est d’affirmer ou d’infirmer cette hypothèse. Les analyses pétrographiques ont tout d’abord permis de séparer le matériel non céramique (torchis et poids de tisserand) des céramiques et des fusaïoles. Le premier groupe est fait d’une argile riche en inclusions et carbonatée ; le torchis n’étant pas dégraissé, contrairement au poids de tisserand (dégraissé par de la matière organique). Les céramiques, en revanche, sont formées d’une argile siliceuse contenant peu d’inclusions et sont dégraissées. Les céramiques ont ensuite été séparées en 10 groupes pétrographiques différents, en fonction de leur argile et de leur plus important dégraissant (granite, gabbro, rhyolite, chert, chamotte ou os). Ces groupes n’ont pas de relation directe avec les groupes typologiques. Les analyses chimiques, quant à elles, ont permis de séparer trois groupes principaux : le matériel non céramique (riche en CaO), les céramiques dégraissées à l’os (riches en P2O5) de la grande majorité des céramiques d’Arbon Bleiche 3. Du point de vue archéologique, les pots Pfyn / Horgen sont locaux. La majorité des céramiques ne pouvant pas être séparées chimiquement, nous pensons qu’elles ont aussi été produites localement. Seuls 13 échantillons sont des exceptions ; ils ne sont donc pas locaux. Malheureusement, leur chimisme ne correspond pas à celui des céramiques du bassin ouest des Carpates, lieu de production supposé (exception peut-être de un échantillon). Leur provenance n’a donc pas pu être élucidée. Seules les caractéristiques typologiques des céramiques de Arbon Bleiche 3 ont un lien avec la Bavière ou le bassin des Carpates.This PhD thesis focuses on the findings from Arbon-Bleiche 3, a Neolithic lacustrine village on the Southern shore of Lake Constance (Bodensee, Switzerland). From 1993 to 1995, 1100 m2 were excavated by the archaeological service of Thurgau (Leuzinger, 2000). The settlement was occupied during a very short period, fifteen years (3384-3370 BC) in the transitional period between Pfyn (3900- 3600 BC) and Horgen (3200-2800 BC) cultures. Dr. A. De Capitani studied the ceramics from Arbon-Bleiche 3. She observed in the ceramics several characteristics of Pfyn culture and of Horgen tradition. She made a typological classification of the ceramics separating Pfyn / Horgen pots from diverse kinds of special forms divided into four sub-groups: special forms Pfyn, special forms Bayern, special forms Boleráz and undetermined special forms. Special forms Pfyn have characteristics from the Pfyn culture, special forms Bayern have specificities in relation with Altheim and Cham cultures in Bavaria, and special forms Boleráz were related to the Boleráz stage of the Baden culture (western Carpathian Basin). For DE CAPITANI (2002), Pfyn / Horgen pots and special forms Pfyn were probably local. A research to detect a possible travel of the other special forms across Europe had to be made. This is the principal goal of this study. First, petrographical analyses permitted to separate non-ceramic material (cob fragments and loom weight) from the ceramics and spindle whorls. The first group was made of an inclusion-rich and carbonate-rich clay, without temper for the cobs and with organic temper for the loom weight. Inversely, the ceramics were manufactured with an inclusion-poor and silicate-rich clay and tempered in various ways. The ceramics were then separated into ten petrographical group according to the clay used and the main temper added (i.e. granite, gabbro, chert, rhyolite, grog and bone). These groups were not in direct relation with the typological groups of DE CAPITANI (2002). Second, chemical analyses let three main groups separate: non-ceramic material (CaO-rich) vs. bone tempered ceramics (P2O5-rich) vs. the great majority of the ceramics from Arbon Bleiche 3. From an archaeological point of view, the Pfyn / Horgen pots are thought to be local. Moreover, because the ceramics cannot be chemically split into groups, the same provenance for the other ceramics is also proposed. Only 13 samples are outliers and were surely foreign. However, a study of 14 ceramics from the western Carpathian Basin (probable import area defined by the archaeologists) did not match the chemistry of the outliers (except maybe one). Their provenance was, hence, not elucidated. Only their typological features are bound to Bavaria or to the western Carpathian Basin
Bichromatic Local Oscillator for Detection of Two-Mode Squeezed States of Light
We present a new technique for the detection of two-mode squeezed states of
light that allows for a simple characterization of these quantum states. The
usual detection scheme, based on heterodyne measurements, requires the use of a
local oscillator with a frequency equal to the mean of the frequencies of the
two modes of the squeezed field. As a result, unless the two modes are close in
frequency, a high-frequency shot-noise-limited detection system is needed. We
propose the use of a bichromatic field as the local oscillator in the
heterodyne measurements. By the proper selection of the frequencies of the
bichromatic field, it is possible to arbitrarily select the frequency around
which the squeezing information is located, thus making it possible to use a
low-bandwidth detection system and to move away from any excess noise present
in the system.Comment: 11 pages, 3 figure
- …