Operational multipartite entanglement classes for symmetric photonic qubit states

We present experimental schemes that allow to study the entanglement classes of all symmetric states in multiqubit photonic systems. In addition to comparing the presented schemes in efficiency, we will highlight the relation between the entanglement properties of symmetric Dicke states and a recently proposed entanglement scheme for atoms. In analogy to the latter, we obtain a one-to-one correspondence between well-defined sets of experimental parameters and multiqubit entanglement classes inside the symmetric subspace of the photonic system.Comment: 5 pages, 1 figur

Unconditional two-mode squeezing of separated atomic ensembles

We propose schemes for the unconditional preparation of a two-mode squeezed state of effective bosonic modes realized in a pair of atomic ensembles interacting collectively with optical cavity and laser fields. The scheme uses Raman transitions between stable atomic ground states and under ideal conditions produces pure entangled states in the steady state. The scheme works both for ensembles confined within a single cavity and for ensembles confined in separate, cascaded cavities.Comment: 4 pages, 2 figure

Restricted dog leucocyte antigen (DLA) class II haplotypes and genotypes in Beagles

AbstractBeagles are commonly used in vaccine trials as part of the regulatory approval process. Genetic restriction within this breed and the impact this might have on vaccine responses are rarely considered. This study was designed to characterise diversity of dog leucocyte antigen (DLA) class II genes in a breeding colony of laboratory Beagles, whose offspring are used in vaccine studies. DLA haplotypes were determined by PCR and sequence-based typing from genomic DNA extracted from blood. Breeding colony Beagles had significantly different DLA haplotype frequencies in comparison with pet Beagles and both groups showed limited DLA diversity. Restricted DLA class II genetic variability within Beagles might result in selective antigen presentation and vaccine responses that are not necessarily representative of those seen in other dog breeds

White-etching matter in bearing steel. Part I: Controlled cracking of 52100 steel

Although most of the research performed in bearing steel metallurgy aims to prevent crack nucleation and propagation, some applications require the exact opposite in order to study the role that disconnected surfaces inside the bulk material play when load is applied, or when fluids entrapped in surface cracks propagate tensile stresses or exacerbate corrosion. Four heat treatments have been designed to create controlled arrays of crack types and distributions in quenched and untempered steel normally used in the manufacture of bearings. The varieties of cracks studied include sparsely distributed martensite-plate cracks, fine-grain-boundary cracks, abundant martensite-plate cracks, and surface cracks. The intention was to create samples which can then be subjected to appropriate mechanical testing so that phenomena such as the appearance of “white-etching areas” or “white-etching cracks,” crack-lubricant interactions, or hydrogen trapping can be studied further.W. Solano-Alvarez is thankful to CONACyT, the Cambridge Overseas Trusts, and the Roberto Rocca Education Program for financial support.This is the accepted manuscript version. The final published version of the article is available from Springer at http://link.springer.com/article/10.1007%2Fs11661-014-2430-y

Exact Mapping of the 2+1 Dirac Oscillator onto the Jaynes-Cummings Model: Ion-Trap Experimental Proposal

We study the dynamics of the 2+1 Dirac oscillator exactly and find spin oscillations due to a {\it Zitterbewegung} of purely relativistic origin. We find an exact mapping of this quantum-relativistic system onto a Jaynes-Cummings model, describing the interaction of a two-level atom with a quantized single-mode field. This equivalence allows us to map a series of quantum optical phenomena onto the relativistic oscillator, and viceversa. We make a realistic experimental proposal, at reach with current technology, for studying the equivalence of both models using a single trapped ion.Comment: Revtex4, submitted for publicatio

Degradation of nanostructured bainitic steel under rolling contact fatigue

The consequences of rolling contact fatigue on carbide-free nanostructured bainite intended for bearing applications are presented for the first time. Tests performed at various intervals followed by mechanical, microscopical, and crystallographic characterisation lead to the conclusion that the degradation mechanism is ductile void formation at interfaces, followed by growth and coalescence into larger voids that lead to fracture along the direction of the softer phase. This is di↵erent from the conventional damage mechanism that involves crack initiation at inclusions and propagation, for example in typical bearings steels such as 52100. The huge density of interfaces in the nanostructure allows the formation of a large dispersion of voids, and ultimately cracks, at depths consistent with the maximum orthogonal shear stress which occurs below the contact surface. This study should prove useful for the eventual usage of nanostructured bainitic steels in rolling bearings.Funding by CONACyT, the Cambridge Overseas Trust, and the Roberto Rocca Education Programme is highly appreciated and acknowledged.This is the accepted manuscript version. The final published version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0921509314010715

A new vertebrate species native to the British isles: Bufo spinosus Daudin, 1803 in Jersey

Recent molecular and morphological studies have shown that Bufo bufo and B. spinosus are genetically distinct and morphologically diagnosable across a relatively narrow contact zone in northern France and should be regarded as different species. However, the species identity of the neighbouring populations of Bufo on the British Channel Island of Jersey has not been investigated. We here present new molecular (a mtDNA RFLP assay plus sequences of the nuclear RAG1 gene) and morphological evidence that these populations are to be assigned to B. spinosus, and can thus be considered an addition to the native British herpetofauna. Jersey toad populations are declining and have a distinct breeding ecology compared to other populations in mainland Britain. We discuss the results in the light of amphibian conservation efforts in Jersey.Fieldwork and sampling in Jersey was conducted under licence from the States of Jersey Environment Department and with support from Amphibian and Reptile Conservation. Other funds were provided by grants CGL2008-04271-C02-01/BOS and CGL2011-28300 (Ministerio de Ciencia e Innovación, Ministerio de Economía y Competitividad, Spain, and FEDER) and PPII10-0097- 4200 (Junta de Comunidades de Castilla la Mancha and FEDER) to IMS, who is currently funded by Project “Biodiversity, Ecology and Global Change”, co-financed by North Portugal Regional Operational Programme 2007/2013 (ON.2–O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF).Peer Reviewe