Algebraic quantization of the closed bosonic string

The gauge invariant observables of the closed bosonic string are quantized without anomalies in four space-time dimensions by constructing their quantum algebra in a manifestly covariant approach. The quantum algebra is the kernel of a derivation on the universal envelopping algebra of an infinite-dimensional Lie algebra. The search for Hilbert space representations of this algebra is separated from its construction, and postponed.Comment: 22 pages. Revised: minor changes as in the published version (CMP

Bullion production in imperial China and its significance for sulphide ore smelting world-wide

Gold and silver production was of major importance for almost all ancient societies but has been rarely studied archaeologically. Here we present a reconstruction of a previously undocumented technology used to recover gold, silver and lead at the site of Baojia in Jiangxi province, China dated between the 7th and 13th centuries AD. Smelting a mixture of sulphidic and gossan ores in a relatively low temperature furnace under mildly reducing conditions, the process involved the use of metallic iron to reduce lead sulphide to lead metal, which acted as the collector of the precious metals. An experimental reconstruction provides essential information, demonstrating both the significant influence of sulphur on the silicate slag system, and that iron reduction smelting of lead can be carried out at a relatively low temperature. These new findings are relevant for further studies of lead and precious metal smelting slags world-wide. The technological choices of ancient smelters at this site are then discussed in their specific geographical and social-economic settings

Pyrotechnological connections? Re-investigating the link between pottery firing technology and the origins of metallurgy in the Vinča Culture, Serbia

The present paper re-examines the purported relationship between Late Neolithic/Early Chalcolithic pottery firing technology and the world's earliest recorded copper metallurgy at two Serbian Vinča culture sites, Belovode and Pločnik (c. 5350 to 4600 BC). A total of eighty-eight well-dated sherds including dark-burnished and graphite-painted pottery that originate across this period have been analysed using a multi-pronged scientific approach in order to reconstruct the raw materials and firing conditions that were necessary for the production of these decorative styles. This is then compared to the pyrotechnological requirements and chronology of copper smelting in order to shed new light on the assumed, yet rarely investigated, hypothesis that advances in pottery firing technology in the late 6th and early 5th millennia BC Balkans were an important precursor for the emergence of metallurgy in this region at around 5000 BC. The results of this study and the recent literature indicate that the ability to exert sufficiently close control over the redox atmosphere in a two-step firing process necessary to produce graphite-painted pottery could indeed link these two crafts. However, graphite-painted pottery and metallurgy emerge at around the same time, both benefitting from the pre-existing experience with dark-burnished pottery and an increasing focus on aesthetics and exotic minerals. Thus, they appear as related technologies, but not as one being the precursor to the other

Protecting the conformal symmetry via bulk renormalization on Anti deSitter space

The problem of perturbative breakdown of conformal symmetry can be avoided, if a conformally covariant quantum field phi on d-dimensional Minkowski spacetime is viewed as the boundary limit of a quantum field Phi on d+1-dimensional anti-deSitter spacetime (AdS). We study the boundary limit in renormalized perturbation theory with polynomial interactions in AdS, and point out the differences as compared to renormalization directly on the boundary. In particular, provided the limit exists, there is no conformal anomaly. We compute explicitly the "fish diagram" on AdS_4 by differential renormalization, and calculate the anomalous dimension of the composite boundary field phi^2 with bulk interaction Phi^4.Comment: 40 page

Supporting Spatial Management of Data-Poor, Small-Scale Fisheries With a Bayesian Approach

Marine conservation areas are an important tool for the sustainable management of multispecies, small-scale fisheries. Effective spatial management requires a proper understanding of the spatial distribution of target species and the identification of its environmental drivers. Small-scale fisheries, however, often face scarcity and low-quality of data. In these situations, approaches for the prioritization of conservation areas need to deal with scattered, biased, and short-term information and ideally should quantify data- and model-specific uncertainties for a better understanding of the risks related to management interventions. We used a Bayesian hierarchical species distribution modeling approach on annual landing data of the heavily exploited, small-scale, and data-poor fishery of Chwaka Bay (Zanzibar) in the Western Indian Ocean to understand the distribution of the key target species and identify potential areas for conservation. Few commonalities were found in the set of important habitat and environmental drivers among species, but temperature, depth, and seagrass cover affected the spatial distribution of three of the six analyzed species. A comparison of our results with information from ecological studies suggests that our approach predicts the distribution of the analyzed species reasonably well. Furthermore, the two main common areas of high relative abundance identified in our study have been previously suggested by the local fisher as important areas for spatial conservation. By using short-term, catch per unit of effort data in a Bayesian hierarchical framework, we quantify the associated uncertainties while accounting for spatial dependencies. More importantly, the use of accessible and interpretable tools, such as the here created spatial maps, can frame a better understanding of spatio-temporal management for local fishers. Our approach, thus, supports the operability of spatial management in small-scale fisheries suffering from a general lack of long-term fisheries information and fisheries independent data.En prens

Lisht as a New Kingdom glass-making site with its own chemical signature

Lisht is one of a few New Kingdom sites with known glass-working debris. Here, we present evidence for the primary production of glass at Lisht, including crucible fragments and semi-finished glass. We also provide 12 new chemical analyses of glass from Lisht, including trace elements. We argue that the glass made at Lisht has a specific chemical signature within the broader range of Late Bronze Age glass compositions from Egypt, further underlining the former existence of primary glass production there and offering the possibility of identifying Lisht-made glass elsewhere in Egypt and beyond

CFT fusion rules, DHR gauge groups, and CAR algebras

It is demonstrated that several series of conformal field theories, while satisfying braid group statistics, can still be described in the conventional setting of the DHR theory, i.e. their superselection structure can be understood in terms of a compact DHR gauge group. Besides theories with only simple sectors, these include (the untwisted part of) c=1 orbifold theories and level two so(N) WZW theories. We also analyze the relation between these models and theories of complex free fermions.Comment: 22 pages, LaTeX2

Polynomial rings of the chiral SU(N)2SU(N)_{2} models

Via explicit diagonalization of the chiral $SU(N)_{2}$ fusion matrices, we discuss the possibility of representing the fusion ring of the chiral SU(N) models, at level K=2, by a polynomial ring in a single variable when $N$ is odd and by a polynomial ring in two variables when $N$ is even.Comment: 10 pages, LaTex (ioplppt.sty

The origins and evolution of Cypriot glazed ware productions during the thirteenth to seventeenth centuries CE

AbstractThis paper challenges the conventional characterisation of glazed ware productions in the eastern Mediterranean, especially the ones which did not feature the use of opaque or tin-glazed technology, as technologically stagnant and unsusceptible to broader socio-economic developments from the late medieval period onwards. Focusing on the Cypriot example, we devise a new approach that combines scientific analyses (thin-section petrography and SEM-EDS) and a full consideration of the chaîne opératoire in context to highlight the changes in technology and craft organisation of glazed ware productions concentrating in the Paphos, Famagusta and Lapithos region during the thirteenth to seventeenth centuries CE. Our results indicate that the Paphos production was short-lived, lasting from the establishment of Frankish rule in Cyprus in the thirteenth century to the aftermath of the fall of the Crusader campaigns in the fourteenth century. However, glazed ware production continued in Famagusta and Lapithos from the late thirteenth/fourteenth centuries through to the seventeenth century, using technical practices that were evidently different from the Paphos production. It is possible that these productions were set up to serve the new, local demands deriving from an intensification of commercial activities on the island. Further changes occurred to the technical practices of the Famagusta and Lapithos productions around the 16th/17th centuries, coinciding with the displacement of populations and socio-political organisation brought by the Ottoman rule.</jats:p

Stable quantum systems in anti-de Sitter space: Causality, independence and spectral properties

If a state is passive for uniformly accelerated observers in n-dimensional anti-de Sitter space-time (i.e. cannot be used by them to operate a perpetuum mobile), they will (a) register a universal value of the Unruh temperature, (b) discover a PCT symmetry, and (c) find that observables in complementary wedge-shaped regions necessarily commute with each other in this state. The stability properties of such a passive state induce a "geodesic causal structure" on AdS and concommitant locality relations. It is shown that observables in these complementary wedge-shaped regions fulfill strong additional independence conditions. In two-dimensional AdS these even suffice to enable the derivation of a nontrivial, local, covariant net indexed by bounded spacetime regions. All these results are model-independent and hold in any theory which is compatible with a weak notion of space-time localization. Examples are provided of models satisfying the hypotheses of these theorems.Comment: 27 pages, 1 figure: dedicated to Jacques Bros on the occasion of his 70th birthday. Revised version: typos corrected; as to appear in J. Math. Phy